Publications by authors named "Jane Juusola"

91 Publications

Functionally impaired RPL8 variants associated with Diamond-Blackfan anemia and a Diamond-Blackfan anemia-like phenotype.

Hum Mutat 2021 Dec 28. Epub 2021 Dec 28.

Molecular, Cellular and Developmental biology department (MCD), Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UT3, Toulouse, France.

Diamond-Blackfan anemia is a rare genetic disease characterized by erythroblastopenia and a large spectrum of developmental anomalies. The vast majority of the cases genetically described are linked to heterozygous pathogenic variants in more than 20 ribosomal protein genes. Here we report an atypical clinical case of DBA associated with a missense variant in RPL8, which encodes RPL8/uL2, a protein of the 60S large ribosomal subunit. RPL8 has been previously implicated as a candidate disease gene in one patient with DBA bearing another type of missense variant; however, evidence for pathogenicity was limited to computational tools. Using functional studies in lymphoblastoid cells as well as yeast models, we show that the RPL8 variants detected in these two patients encode functionally deficient proteins that affect ribosome production and are therefore likely pathogenic. We propose to include RPL8 in the list of DBA-associated genes.
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http://dx.doi.org/10.1002/humu.24323DOI Listing
December 2021

Compound Heterozygous Mutations in ZNF408 in a Patient with a Late Onset Pigmentary Retinopathy and Relatively Preserved Central Retina.

Doc Ophthalmol 2021 12 14;143(3):305-312. Epub 2021 Jul 14.

Scheie Eye Institute at the Perelman Center for Advanced Medicine, Department of Ophthalmology, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA, 19104, USA.

Purpose: To describe in detail the phenotype of a patient with compound heterozygous mutations in ZNF408 and an adult-onset pigmentary retinopathy rather than familial exudative vitreoretinopathy as expected with heterozygous mutations in this gene.

Methods: A 70-year-old male presented with a pigmentary retinopathy, which prompted a genetic evaluation that revealed two variants in trans in the ZNF408 gene. He underwent an ophthalmic examination, kinetic fields, electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence, wide-angle fluorescein angiography and near-infrared imaging.

Results: Visual acuity was 20/20 for both eyes. Fundus examination showed epiretinal membrane, vascular attenuation and peripheral bone spicule pigmentation in both eyes. Fluorescein angiography showed no vascular anomalies in both eyes. Fundus autofluorescence showed a preserved island of fundus autofluorescence centrally. Visual field by kinetic perimetry (V-4e stimulus) showed generalized constriction to 40 degrees of eccentricity and by an I-4e target showed generalized constriction to 10 degrees of eccentricity. ERG showed detectable but reduced cone-mediated responses. SD-OCT demonstrated preserved outer nuclear layer thickness centrally, which decreased with eccentricity. Static perimetry showed substantial rod and cone sensitivities centrally that declined with eccentricity. A next-generation sequencing panel revealed bi-allelic variants (p.Arg567Ter; c.1699C > T and p.Leu566His; c.1697 T > A) in the ZNF408 gene.

Conclusions: ZNF408-associated retinal dystrophies can present with predominantly retinal findings and should be considered in the differential diagnosis of retinitis pigmentosa. Our study revealed a novel variant p.L566H, which to our knowledge has not previously been reported.
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http://dx.doi.org/10.1007/s10633-021-09847-7DOI Listing
December 2021

UBA2 variants underlie a recognizable syndrome with variable aplasia cutis congenita and ectrodactyly.

Genet Med 2021 09 26;23(9):1624-1635. Epub 2021 May 26.

National Eye Institute, National Institutes of Health, Bethesda, MD, USA.

Purpose: The human chromosome 19q13.11 deletion syndrome is associated with a variable phenotype that includes aplasia cutis congenita (ACC) and ectrodactyly as specific features. UBA2 (ubiquitin-like modifier-activating enzyme 2) lies adjacent to the minimal deletion overlap region. We aimed to define the UBA2-related phenotypic spectrum in humans and zebrafish due to sequence variants and to establish the mechanism of disease.

Methods: Exome sequencing was used to detect UBA2 sequence variants in 16 subjects in 7 unrelated families. uba2 loss of function was modeled in zebrafish. Effects of human missense variants were assessed in zebrafish rescue experiments.

Results: Seven human UBA2 loss-of-function and missense sequence variants were detected. UBA2-phenotypes included ACC, ectrodactyly, neurodevelopmental abnormalities, ectodermal, skeletal, craniofacial, cardiac, renal, and genital anomalies. uba2 was expressed in zebrafish eye, brain, and pectoral fins; uba2-null fish showed deficient growth, microcephaly, microphthalmia, mandibular hypoplasia, and abnormal fins. uba2-mRNAs with human missense variants failed to rescue nullizygous zebrafish phenotypes.

Conclusion: UBA2 variants cause a recognizable syndrome with a wide phenotypic spectrum. Our data suggest that loss of UBA2 function underlies the human UBA2 monogenic disorder and highlights the importance of SUMOylation in the development of affected tissues.
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http://dx.doi.org/10.1038/s41436-021-01182-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8463496PMC
September 2021

Non-coding region variants upstream of MEF2C cause severe developmental disorder through three distinct loss-of-function mechanisms.

Am J Hum Genet 2021 06 21;108(6):1083-1094. Epub 2021 May 21.

Human Genetics Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1RQ, UK; East Anglian Medical Genetics Service, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK.

Clinical genetic testing of protein-coding regions identifies a likely causative variant in only around half of developmental disorder (DD) cases. The contribution of regulatory variation in non-coding regions to rare disease, including DD, remains very poorly understood. We screened 9,858 probands from the Deciphering Developmental Disorders (DDD) study for de novo mutations in the 5' untranslated regions (5' UTRs) of genes within which variants have previously been shown to cause DD through a dominant haploinsufficient mechanism. We identified four single-nucleotide variants and two copy-number variants upstream of MEF2C in a total of ten individual probands. We developed multiple bespoke and orthogonal experimental approaches to demonstrate that these variants cause DD through three distinct loss-of-function mechanisms, disrupting transcription, translation, and/or protein function. These non-coding region variants represent 23% of likely diagnoses identified in MEF2C in the DDD cohort, but these would all be missed in standard clinical genetics approaches. Nonetheless, these variants are readily detectable in exome sequence data, with 30.7% of 5' UTR bases across all genes well covered in the DDD dataset. Our analyses show that non-coding variants upstream of genes within which coding variants are known to cause DD are an important cause of severe disease and demonstrate that analyzing 5' UTRs can increase diagnostic yield. We also show how non-coding variants can help inform both the disease-causing mechanism underlying protein-coding variants and dosage tolerance of the gene.
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http://dx.doi.org/10.1016/j.ajhg.2021.04.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8206381PMC
June 2021

Genotype-phenotype correlations and novel molecular insights into the DHX30-associated neurodevelopmental disorders.

Genome Med 2021 05 21;13(1):90. Epub 2021 May 21.

Département de Génétique, Hôpital La Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.

Background: We aimed to define the clinical and variant spectrum and to provide novel molecular insights into the DHX30-associated neurodevelopmental disorder.

Methods: Clinical and genetic data from affected individuals were collected through Facebook-based family support group, GeneMatcher, and our network of collaborators. We investigated the impact of novel missense variants with respect to ATPase and helicase activity, stress granule (SG) formation, global translation, and their effect on embryonic development in zebrafish. SG formation was additionally analyzed in CRISPR/Cas9-mediated DHX30-deficient HEK293T and zebrafish models, along with in vivo behavioral assays.

Results: We identified 25 previously unreported individuals, ten of whom carry novel variants, two of which are recurrent, and provide evidence of gonadal mosaicism in one family. All 19 individuals harboring heterozygous missense variants within helicase core motifs (HCMs) have global developmental delay, intellectual disability, severe speech impairment, and gait abnormalities. These variants impair the ATPase and helicase activity of DHX30, trigger SG formation, interfere with global translation, and cause developmental defects in a zebrafish model. Notably, 4 individuals harboring heterozygous variants resulting either in haploinsufficiency or truncated proteins presented with a milder clinical course, similar to an individual harboring a de novo mosaic HCM missense variant. Functionally, we established DHX30 as an ATP-dependent RNA helicase and as an evolutionary conserved factor in SG assembly. Based on the clinical course, the variant location, and type we establish two distinct clinical subtypes. DHX30 loss-of-function variants cause a milder phenotype whereas a severe phenotype is caused by HCM missense variants that, in addition to the loss of ATPase and helicase activity, lead to a detrimental gain-of-function with respect to SG formation. Behavioral characterization of dhx30-deficient zebrafish revealed altered sleep-wake activity and social interaction, partially resembling the human phenotype.

Conclusions: Our study highlights the usefulness of social media to define novel Mendelian disorders and exemplifies how functional analyses accompanied by clinical and genetic findings can define clinically distinct subtypes for ultra-rare disorders. Such approaches require close interdisciplinary collaboration between families/legal representatives of the affected individuals, clinicians, molecular genetics diagnostic laboratories, and research laboratories.
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http://dx.doi.org/10.1186/s13073-021-00900-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8140440PMC
May 2021

Variants in the degron of AFF3 are associated with intellectual disability, mesomelic dysplasia, horseshoe kidney, and epileptic encephalopathy.

Am J Hum Genet 2021 05;108(5):857-873

GeneDx, Gaithersburg, MD 20877, USA.

The ALF transcription factor paralogs, AFF1, AFF2, AFF3, and AFF4, are components of the transcriptional super elongation complex that regulates expression of genes involved in neurogenesis and development. We describe an autosomal dominant disorder associated with de novo missense variants in the degron of AFF3, a nine amino acid sequence important for its binding to ubiquitin ligase, or with de novo deletions of this region. The sixteen affected individuals we identified, along with two previously reported individuals, present with a recognizable pattern of anomalies, which we named KINSSHIP syndrome (KI for horseshoe kidney, NS for Nievergelt/Savarirayan type of mesomelic dysplasia, S for seizures, H for hypertrichosis, I for intellectual disability, and P for pulmonary involvement), partially overlapping the AFF4-associated CHOPS syndrome. Whereas homozygous Aff3 knockout mice display skeletal anomalies, kidney defects, brain malformations, and neurological anomalies, knockin animals modeling one of the microdeletions and the most common of the missense variants identified in affected individuals presented with lower mesomelic limb deformities like KINSSHIP-affected individuals and early lethality, respectively. Overexpression of AFF3 in zebrafish resulted in body axis anomalies, providing some support for the pathological effect of increased amount of AFF3. The only partial phenotypic overlap of AFF3- and AFF4-associated syndromes and the previously published transcriptome analyses of ALF transcription factors suggest that these factors are not redundant and each contributes uniquely to proper development.
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http://dx.doi.org/10.1016/j.ajhg.2021.04.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8206167PMC
May 2021

Heterozygous ANKRD17 loss-of-function variants cause a syndrome with intellectual disability, speech delay, and dysmorphism.

Am J Hum Genet 2021 06 27;108(6):1138-1150. Epub 2021 Apr 27.

Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143, USA.

ANKRD17 is an ankyrin repeat-containing protein thought to play a role in cell cycle progression, whose ortholog in Drosophila functions in the Hippo pathway as a co-factor of Yorkie. Here, we delineate a neurodevelopmental disorder caused by de novo heterozygous ANKRD17 variants. The mutational spectrum of this cohort of 34 individuals from 32 families is highly suggestive of haploinsufficiency as the underlying mechanism of disease, with 21 truncating or essential splice site variants, 9 missense variants, 1 in-frame insertion-deletion, and 1 microdeletion (1.16 Mb). Consequently, our data indicate that loss of ANKRD17 is likely the main cause of phenotypes previously associated with large multi-gene chromosomal aberrations of the 4q13.3 region. Protein modeling suggests that most of the missense variants disrupt the stability of the ankyrin repeats through alteration of core structural residues. The major phenotypic characteristic of our cohort is a variable degree of developmental delay/intellectual disability, particularly affecting speech, while additional features include growth failure, feeding difficulties, non-specific MRI abnormalities, epilepsy and/or abnormal EEG, predisposition to recurrent infections (mostly bacterial), ophthalmological abnormalities, gait/balance disturbance, and joint hypermobility. Moreover, many individuals shared similar dysmorphic facial features. Analysis of single-cell RNA-seq data from the developing human telencephalon indicated ANKRD17 expression at multiple stages of neurogenesis, adding further evidence to the assertion that damaging ANKRD17 variants cause a neurodevelopmental disorder.
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http://dx.doi.org/10.1016/j.ajhg.2021.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8206162PMC
June 2021

First case of pan-suture craniosynostosis due to de novo mosaic KAT6A mutation.

Childs Nerv Syst 2022 Jan 26;38(1):173-177. Epub 2021 Mar 26.

Helen DeVos Children's Hospital (Neurosurgery), 35 Michigan St. NE, Suite 3003, Grand Rapids, MI, 49503, USA.

A nonverbal 3-year-old male with a complex past medical history was referred to pediatric neurosurgery for evaluation of Chiari I malformation. A full clinical evaluation suggested that the "Chiari" was a secondary change caused by craniocerebral disproportion that was the result of delayed pan-sutural craniosynostosis. Given his unknown cause of craniosynostosis, whole-exome sequencing (WES) was performed. WES revealed a de novo, somatic mosaic variant in the KAT6A gene. This report discusses importance of keeping a broad differential in the setting of referral for Chiari I malformation and presents a unique case of craniosynostosis. Additionally, it emphasizes the value of utilizing genetic testing for complex craniofacial cases with unknown causes to provide clinical answers and guide clinical management.
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http://dx.doi.org/10.1007/s00381-021-05111-0DOI Listing
January 2022

TAOK1 is associated with neurodevelopmental disorder and essential for neuronal maturation and cortical development.

Hum Mutat 2021 04 1;42(4):445-459. Epub 2021 Mar 1.

Department of Pediatrics, SIU School of Medicine, Springfield, Illinois, USA.

Thousand and one amino-acid kinase 1 (TAOK1) is a MAP3K protein kinase, regulating different mitogen-activated protein kinase pathways, thereby modulating a multitude of processes in the cell. Given the recent finding of TAOK1 involvement in neurodevelopmental disorders (NDDs), we investigated the role of TAOK1 in neuronal function and collected a cohort of 23 individuals with mostly de novo variants in TAOK1 to further define the associated NDD. Here, we provide evidence for an important role for TAOK1 in neuronal function, showing that altered TAOK1 expression levels in the embryonic mouse brain affect neural migration in vivo, as well as neuronal maturation in vitro. The molecular spectrum of the identified TAOK1 variants comprises largely truncating and nonsense variants, but also missense variants, for which we provide evidence that they can have a loss of function or dominant-negative effect on TAOK1, expanding the potential underlying causative mechanisms resulting in NDD. Taken together, our data indicate that TAOK1 activity needs to be properly controlled for normal neuronal function and that TAOK1 dysregulation leads to a neurodevelopmental disorder mainly comprising similar facial features, developmental delay/intellectual disability and/or variable learning or behavioral problems, muscular hypotonia, infant feeding difficulties, and growth problems.
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http://dx.doi.org/10.1002/humu.24176DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8248425PMC
April 2021

Uniparental disomy in a population of 32,067 clinical exome trios.

Genet Med 2021 06 25;23(6):1101-1107. Epub 2021 Jan 25.

GeneDx, Gaithersburg, MD, USA.

Purpose: Data on the clinical prevalence and spectrum of uniparental disomy (UPD) remain limited. Trio exome sequencing (ES) presents a comprehensive method for detection of UPD alongside sequence and copy-number variant analysis.

Methods: We analyzed 32,067 ES trios referred for diagnostic testing to create a profile of UPD events and their disease associations. ES single-nucleotide polymorphism (SNP) and copy-number data were used to identify both whole-chromosome and segmental UPD and to categorize whole-chromosome results as isodisomy, heterodisomy, or mixed.

Results: Ninety-nine whole-chromosome and 13 segmental UPD events were identified. Of these, 29 were associated with an imprinting disorder, and 16 were associated with a positive test result through homozygous sequence variants. Isodisomy was more commonly observed in large chromosomes along with a higher rate of homozygous pathogenic variants, while heterodisomy was more frequent in chromosomes associated with imprinting or trisomy mosaicism (14, 15, 16, 20, 22).

Conclusion: Whole-chromosome UPD was observed in 0.31% of cases, resulting in a diagnostic finding in 0.14%. Only three UPD-positive cases had a diagnostic finding unrelated to the UPD. Thirteen UPD events were identified in cases with prior normal SNP chromosomal microarray results, demonstrating the additional diagnostic value of UPD detection by trio ES.
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http://dx.doi.org/10.1038/s41436-020-01092-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8187148PMC
June 2021

Variants in GNAI1 cause a syndrome associated with variable features including developmental delay, seizures, and hypotonia.

Genet Med 2021 05 20;23(5):881-887. Epub 2021 Jan 20.

Duke University Health System, Durham, NC, USA.

Purpose: Neurodevelopmental disorders (NDDs) encompass a spectrum of genetically heterogeneous disorders with features that commonly include developmental delay, intellectual disability, and autism spectrum disorders. We sought to delineate the molecular and phenotypic spectrum of a novel neurodevelopmental disorder caused by variants in the GNAI1 gene.

Methods: Through large cohort trio-based exome sequencing and international data-sharing, we identified 24 unrelated individuals with NDD phenotypes and a variant in GNAI1, which encodes the inhibitory Gαi1 subunit of heterotrimeric G-proteins. We collected detailed genotype and phenotype information for each affected individual.

Results: We identified 16 unique variants in GNAI1 in 24 affected individuals; 23 occurred de novo and 1 was inherited from a mosaic parent. Most affected individuals have a severe neurodevelopmental disorder. Core features include global developmental delay, intellectual disability, hypotonia, and epilepsy.

Conclusion: This collaboration establishes GNAI1 variants as a cause of NDDs. GNAI1-related NDD is most often characterized by severe to profound delays, hypotonia, epilepsy that ranges from self-limiting to intractable, behavior problems, and variable mild dysmorphic features.
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http://dx.doi.org/10.1038/s41436-020-01076-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8107131PMC
May 2021

MEIS2 sequence variant in a child with intellectual disability and cardiac defects: Expansion of the phenotypic spectrum and documentation of low-level mosaicism in an unaffected parent.

Am J Med Genet A 2021 01 22;185(1):300-303. Epub 2020 Oct 22.

Genetics Program, North York General Hospital, Toronto, Canada.

Deletions and pathogenic sequence variants in Myeloid Ecotropic Insertion Site 2 (MEIS2) gene have been reported to cause a recognizable triad of intellectual disability, congenital heart malformations, and palatal defects. To date, 18 individuals with de novo pathogenic sequence variants in MEIS2 have been reported in the literature, most with all three cardinal features. We recently saw a young boy, almost 3 years of age, who was known to have mosaic XYY syndrome (47,XYY [23]/46,XY[7]). He presented with atrial and ventricular septal defects, developmental delay, facial dysmorphism, gastroesophageal reflux, undescended testicle, a buried penis with penoscrotal transposition, primary neutropenia, and a branchial cleft sinus. Whole-exome sequencing identified a previously reported in-frame pathogenic deletion (c.998_1000delGAA; p.R333del; NM_170674.4) in MEIS2. His unaffected father was confirmed to have low-level mosaicism for the same MEIS2 variant. The proband represents the 19th reported individual with a pathogenic sequence variant in MEIS2 and expands the phenotypic spectrum to include primary neutropenia, branchial anomalies, and complex genital anomalies. Furthermore, to our knowledge this is the first reported case of mosaicism for a variant in this gene in an apparently unaffected parent. This finding would have implications for recurrence risk counseling for families.
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http://dx.doi.org/10.1002/ajmg.a.61929DOI Listing
January 2021

De novo variants in MPP5 cause global developmental delay and behavioral changes.

Hum Mol Genet 2020 12;29(20):3388-3401

Division of Newborn Medicine, Department of Pediatrics, Boston Children's Hospital, Boston, MA 02115, USA.

Membrane Protein Palmitoylated 5 (MPP5) is a highly conserved apical complex protein essential for cell polarity, fate and survival. Defects in cell polarity are associated with neurologic disorders including autism and microcephaly. MPP5 is essential for neurogenesis in animal models, but human variants leading to neurologic impairment have not been described. We identified three patients with heterozygous MPP5 de novo variants (DNV) and global developmental delay (GDD) and compared their phenotypes and magnetic resonance imaging (MRI) to ascertain how MPP5 DNV leads to GDD. All three patients with MPP5 DNV experienced GDD with language delay/regression and behavioral changes. MRI ranged from normal to decreased gyral folding and microcephaly. The effects of MPP5 depletion on the developing brain were assessed by creating a heterozygous conditional knock out (het CKO) murine model with central nervous system (CNS)-specific Nestin-Cre drivers. In the het CKO model, Mpp5 depletion led to microcephaly, decreased cerebellar volume and cortical thickness. Het CKO mice had decreased ependymal cells and Mpp5 at the apical surface of cortical ventricular zone compared with wild type. Het CKO mice also failed to maintain progenitor pools essential for neurogenesis. The proportion of cortical cells undergoing apoptotic cell death increased, suggesting that cell death reduces progenitor population and neuron number. Het CKO mice also showed behavioral changes, similar to our patients. To our knowledge, this is the first report to show that variants in MPP5 are associated with GDD, behavioral abnormalities and language regression/delay. Murine modeling shows that neurogenesis is likely altered in these individuals, with cell death and skewed cellular composition playing significant roles.
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http://dx.doi.org/10.1093/hmg/ddaa224DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906781PMC
December 2020

Evidence for 28 genetic disorders discovered by combining healthcare and research data.

Nature 2020 10 14;586(7831):757-762. Epub 2020 Oct 14.

Human Genetics Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK.

De novo mutations in protein-coding genes are a well-established cause of developmental disorders. However, genes known to be associated with developmental disorders account for only a minority of the observed excess of such de novo mutations. Here, to identify previously undescribed genes associated with developmental disorders, we integrate healthcare and research exome-sequence data from 31,058 parent-offspring trios of individuals with developmental disorders, and develop a simulation-based statistical test to identify gene-specific enrichment of de novo mutations. We identified 285 genes that were significantly associated with developmental disorders, including 28 that had not previously been robustly associated with developmental disorders. Although we detected more genes associated with developmental disorders, much of the excess of de novo mutations in protein-coding genes remains unaccounted for. Modelling suggests that more than 1,000 genes associated with developmental disorders have not yet been described, many of which are likely to be less penetrant than the currently known genes. Research access to clinical diagnostic datasets will be critical for completing the map of genes associated with developmental disorders.
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http://dx.doi.org/10.1038/s41586-020-2832-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116826PMC
October 2020

Aplastic anemia in a patient with CVID due to NFKB1 haploinsufficiency.

Cold Spring Harb Mol Case Stud 2020 12 17;6(6). Epub 2020 Dec 17.

Division of Hematology-Oncology, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.

Acquired aplastic anemia (AA) is a life-threatening bone marrow failure caused by an autoimmune cytotoxic T lymphocyte attack on hematopoietic stem and progenitor cells. Factors contributing to aberrant autoimmune activation in AA include a deficit of T regulatory cells and high levels of inflammatory cytokines. Several acquired conditions of immune dysregulation and genetic polymorphisms in inflammatory cytokines and human leukocyte antigen genes have been linked to an increased risk of AA. However, AA has not been reported in patients with Mendelian disorders of immune regulation. Here we report a patient with familial common variable immunodeficiency (CVID) caused by a pathogenic variant in , who developed AA as an adult. The patient had a difficult clinical course and was unable to tolerate standard AA therapy with cyclosporine A and eltrombopag, with complications attributed in part to the effect of cyclosporine A on NF-κB signaling. Our case suggests a novel link between genetic disorders of immune regulation and AA and highlights the importance of recognizing inherited autoimmunity syndromes in AA patients for the selection of optimal therapy and prognostic counseling.
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http://dx.doi.org/10.1101/mcs.a005769DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7784489PMC
December 2020

A relatively common homozygous TRAPPC4 splicing variant is associated with an early-infantile neurodegenerative syndrome.

Eur J Hum Genet 2021 02 8;29(2):271-279. Epub 2020 Sep 8.

Department of Pediatrics, Ain Shams University, Cairo, Egypt.

Trafficking protein particle (TRAPP) complexes, which include the TRAPPC4 protein, regulate membrane trafficking between lipid organelles in a process termed vesicular tethering. TRAPPC4 was recently implicated in a recessive neurodevelopmental condition in four unrelated families due to a shared c.454+3A>G splice variant. Here, we report 23 patients from 17 independent families with an early-infantile-onset neurodegenerative presentation, where we also identified the homozygous variant hg38:11:119020256 A>G (NM_016146.5:c.454+3A>G) in TRAPPC4 through exome or genome sequencing. No other clinically relevant TRAPPC4 variants were identified among any of over 10,000 patients with neurodevelopmental conditions. We found the carrier frequency of TRAPPC4 c.454+3A>G was 2.4-5.4 per 10,000 healthy individuals. Affected individuals with the homozygous TRAPPC4 c.454+3A>G variant showed profound psychomotor delay, developmental regression, early-onset epilepsy, microcephaly and progressive spastic tetraplegia. Based upon RNA sequencing, the variant resulted in partial exon 3 skipping and generation of an aberrant transcript owing to use of a downstream cryptic splice donor site, predicting a premature stop codon and nonsense mediated decay. These data confirm the pathogenicity of the TRAPPC4 c.454+3A>G variant, and refine the clinical presentation of TRAPPC4-related encephalopathy.
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http://dx.doi.org/10.1038/s41431-020-00717-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7868361PMC
February 2021

Biallelic MADD variants cause a phenotypic spectrum ranging from developmental delay to a multisystem disorder.

Brain 2020 08;143(8):2437-2453

Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.

In pleiotropic diseases, multiple organ systems are affected causing a variety of clinical manifestations. Here, we report a pleiotropic disorder with a unique constellation of neurological, endocrine, exocrine, and haematological findings that is caused by biallelic MADD variants. MADD, the mitogen-activated protein kinase (MAPK) activating death domain protein, regulates various cellular functions, such as vesicle trafficking, activity of the Rab3 and Rab27 small GTPases, tumour necrosis factor-α (TNF-α)-induced signalling and prevention of cell death. Through national collaboration and GeneMatcher, we collected 23 patients with 21 different pathogenic MADD variants identified by next-generation sequencing. We clinically evaluated the series of patients and categorized the phenotypes in two groups. Group 1 consists of 14 patients with severe developmental delay, endo- and exocrine dysfunction, impairment of the sensory and autonomic nervous system, and haematological anomalies. The clinical course during the first years of life can be potentially fatal. The nine patients in Group 2 have a predominant neurological phenotype comprising mild-to-severe developmental delay, hypotonia, speech impairment, and seizures. Analysis of mRNA revealed multiple aberrant MADD transcripts in two patient-derived fibroblast cell lines. Relative quantification of MADD mRNA and protein in fibroblasts of five affected individuals showed a drastic reduction or loss of MADD. We conducted functional tests to determine the impact of the variants on different pathways. Treatment of patient-derived fibroblasts with TNF-α resulted in reduced phosphorylation of the extracellular signal-regulated kinases 1 and 2, enhanced activation of the pro-apoptotic enzymes caspase-3 and -7 and increased apoptosis compared to control cells. We analysed internalization of epidermal growth factor in patient cells and identified a defect in endocytosis of epidermal growth factor. We conclude that MADD deficiency underlies multiple cellular defects that can be attributed to alterations of TNF-α-dependent signalling pathways and defects in vesicular trafficking. Our data highlight the multifaceted role of MADD as a signalling molecule in different organs and reveal its physiological role in regulating the function of the sensory and autonomic nervous system and endo- and exocrine glands.
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http://dx.doi.org/10.1093/brain/awaa204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7447524PMC
August 2020

Variants in SCAF4 Cause a Neurodevelopmental Disorder and Are Associated with Impaired mRNA Processing.

Am J Hum Genet 2020 09 29;107(3):544-554. Epub 2020 Jul 29.

University of South Dakota, Sanford School of Medicine, Sioux Falls, SD 57105, USA.

RNA polymerase II interacts with various other complexes and factors to ensure correct initiation, elongation, and termination of mRNA transcription. One of these proteins is SR-related CTD-associated factor 4 (SCAF4), which is important for correct usage of polyA sites for mRNA termination. Using exome sequencing and international matchmaking, we identified nine likely pathogenic germline variants in SCAF4 including two splice-site and seven truncating variants, all residing in the N-terminal two thirds of the protein. Eight of these variants occurred de novo, and one was inherited. Affected individuals demonstrated a variable neurodevelopmental disorder characterized by mild intellectual disability, seizures, behavioral abnormalities, and various skeletal and structural anomalies. Paired-end RNA sequencing on blood lymphocytes of SCAF4-deficient individuals revealed a broad deregulation of more than 9,000 genes and significant differential splicing of more than 2,900 genes, indicating an important role of SCAF4 in mRNA processing. Knockdown of the SCAF4 ortholog CG4266 in the model organism Drosophila melanogaster resulted in impaired locomotor function, learning, and short-term memory. Furthermore, we observed an increased number of active zones in larval neuromuscular junctions, representing large glutamatergic synapses. These observations indicate a role of CG4266 in nervous system development and function and support the implication of SCAF4 in neurodevelopmental phenotypes. In summary, our data show that heterozygous, likely gene-disrupting variants in SCAF4 are causative for a variable neurodevelopmental disorder associated with impaired mRNA processing.
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http://dx.doi.org/10.1016/j.ajhg.2020.06.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7477272PMC
September 2020

De Novo Variants in the ATPase Module of MORC2 Cause a Neurodevelopmental Disorder with Growth Retardation and Variable Craniofacial Dysmorphism.

Am J Hum Genet 2020 08 20;107(2):352-363. Epub 2020 Jul 20.

Clinical Genetics, Stanford Children's Health, San Francisco, CA 94109, USA.

MORC2 encodes an ATPase that plays a role in chromatin remodeling, DNA repair, and transcriptional regulation. Heterozygous variants in MORC2 have been reported in individuals with autosomal-dominant Charcot-Marie-Tooth disease type 2Z and spinal muscular atrophy, and the onset of symptoms ranges from infancy to the second decade of life. Here, we present a cohort of 20 individuals referred for exome sequencing who harbor pathogenic variants in the ATPase module of MORC2. Individuals presented with a similar phenotype consisting of developmental delay, intellectual disability, growth retardation, microcephaly, and variable craniofacial dysmorphism. Weakness, hyporeflexia, and electrophysiologic abnormalities suggestive of neuropathy were frequently observed but were not the predominant feature. Five of 18 individuals for whom brain imaging was available had lesions reminiscent of those observed in Leigh syndrome, and five of six individuals who had dilated eye exams had retinal pigmentary abnormalities. Functional assays revealed that these MORC2 variants result in hyperactivation of epigenetic silencing by the HUSH complex, supporting their pathogenicity. The described set of morphological, growth, developmental, and neurological findings and medical concerns expands the spectrum of genetic disorders resulting from pathogenic variants in MORC2.
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http://dx.doi.org/10.1016/j.ajhg.2020.06.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413887PMC
August 2020

Bi-allelic ADARB1 Variants Associated with Microcephaly, Intellectual Disability, and Seizures.

Am J Hum Genet 2020 04 26;106(4):467-483. Epub 2020 Mar 26.

Central European Institute of Technology, Masaryk University, Kamenice 735/5, A35, Brno 62500, Czech Republic. Electronic address:

The RNA editing enzyme ADAR2 is essential for the recoding of brain transcripts. Impaired ADAR2 editing leads to early-onset epilepsy and premature death in a mouse model. Here, we report bi-allelic variants in ADARB1, the gene encoding ADAR2, in four unrelated individuals with microcephaly, intellectual disability, and epilepsy. In one individual, a homozygous variant in one of the double-stranded RNA-binding domains (dsRBDs) was identified. In the others, variants were situated in or around the deaminase domain. To evaluate the effects of these variants on ADAR2 enzymatic activity, we performed in vitro assays with recombinant proteins in HEK293T cells and ex vivo assays with fibroblasts derived from one of the individuals. We demonstrate that these ADAR2 variants lead to reduced editing activity on a known ADAR2 substrate. We also demonstrate that one variant leads to changes in splicing of ADARB1 transcript isoforms. These findings reinforce the importance of RNA editing in brain development and introduce ADARB1 as a genetic etiology in individuals with intellectual disability, microcephaly, and epilepsy.
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http://dx.doi.org/10.1016/j.ajhg.2020.02.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7118584PMC
April 2020

A phenotypically severe, biochemically "silent" case of HIBCH deficiency in a newborn diagnosed by rapid whole exome sequencing and enzymatic testing.

Am J Med Genet A 2020 04 5;182(4):780-784. Epub 2020 Feb 5.

Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.

3-Hydroxyisobutyryl-CoA dehydrogenase (HIBCH) deficiency is a rare error in valine catabolism associated with a Leigh syndrome-like phenotype, mitochondrial dysfunction, and increased C4-OH. We report the most severe case to date in a full-term female who presented with poor feeding and nystagmus on day of life (DOL) 1. Although initial neuroimaging findings were concerning for metabolic disease, further metabolic testing was nondiagnostic and she was discharged on DOL 18. She was readmitted on DOL 22 after severe apneic episodes requiring intubation, with EEG demonstrating multifocal seizures and MRI/MRS demonstrating worsening findings. Care was withdrawn DOL 27 and she expired. Rapid whole exome sequencing (WES) demonstrated compound heterozygous variants in HIBCH with a paternal pathogenic variant (c.852delA, p.L284FfsX10) and a maternal likely pathogenic variant (c.488G>T, p.C163F). Fibroblast enzymatic testing demonstrated marked reduction in HIBCH levels. This case demonstrates the importance of rapid WES and follow-up functional testing in establishing a diagnosis when metabolic disease is suspected but lacks an expected biochemical signature.
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http://dx.doi.org/10.1002/ajmg.a.61498DOI Listing
April 2020

De novo TBR1 variants cause a neurocognitive phenotype with ID and autistic traits: report of 25 new individuals and review of the literature.

Eur J Hum Genet 2020 06 31;28(6):770-782. Epub 2020 Jan 31.

Department of Pediatrics, The Barbara Bush Children's Hospital, Maine Medical Center, Portland, OR, USA.

TBR1, a T-box transcription factor expressed in the cerebral cortex, regulates the expression of several candidate genes for autism spectrum disorders (ASD). Although TBR1 has been reported as a high-confidence risk gene for ASD and intellectual disability (ID) in functional and clinical reports since 2011, TBR1 has only recently been recorded as a human disease gene in the OMIM database. Currently, the neurodevelopmental disorders and structural brain anomalies associated with TBR1 variants are not well characterized. Through international data sharing, we collected data from 25 unreported individuals and compared them with data from the literature. We evaluated structural brain anomalies in seven individuals by analysis of MRI images, and compared these with anomalies observed in TBR1 mutant mice. The phenotype included ID in all individuals, associated to autistic traits in 76% of them. No recognizable facial phenotype could be identified. MRI analysis revealed a reduction of the anterior commissure and suggested new features including dysplastic hippocampus and subtle neocortical dysgenesis. This report supports the role of TBR1 in ID associated with autistic traits and suggests new structural brain malformations in humans. We hope this work will help geneticists to interpret TBR1 variants and diagnose ASD probands.
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http://dx.doi.org/10.1038/s41431-020-0571-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7253452PMC
June 2020

Mobile element insertion detection in 89,874 clinical exomes.

Genet Med 2020 05 22;22(5):974-978. Epub 2020 Jan 22.

GeneDx, Gaithersburg, MD, USA.

Purpose: Exome sequencing (ES) is increasingly used for the diagnosis of rare genetic disease. However, some pathogenic sequence variants within the exome go undetected due to the technical difficulty of identifying them. Mobile element insertions (MEIs) are a known cause of genetic disease in humans but have been historically difficult to detect via ES and similar targeted sequencing methods.

Methods: We developed and applied a novel MEI detection method prospectively to samples received for clinical ES beginning in November 2017. Positive MEI findings were confirmed by an orthogonal method and reported back to the ordering provider. In this study, we examined 89,874 samples from 38,871 cases.

Results: Diagnostic MEIs were present in 0.03% (95% binomial test confidence interval: 0.02-0.06%) of all cases and account for 0.15% (95% binomial test confidence interval: 0.08-0.25%) of cases with a molecular diagnosis. One diagnostic MEI was a novel founder event. Most patients with pathogenic MEIs had prior genetic testing, three of whom had previous negative DNA sequencing analysis of the diagnostic gene.

Conclusion: MEI detection from ES is a valuable diagnostic tool, reveals molecular findings that may be undetected by other sequencing assays, and increases diagnostic yield by 0.15%.
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http://dx.doi.org/10.1038/s41436-020-0749-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7200591PMC
May 2020

Expanding the genotype-phenotype correlation of de novo heterozygous missense variants in YWHAG as a cause of developmental and epileptic encephalopathy.

Am J Med Genet A 2020 04 11;182(4):713-720. Epub 2020 Jan 11.

Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK.

Developmental and Epileptic encephalopathies (DEE) describe heterogeneous epilepsy syndromes, characterized by early-onset, refractory seizures and developmental delay (DD). Several DEE associated genes have been reported. With increased access to whole exome sequencing (WES), new candidate genes are being identified although there are fewer large cohort papers describing the clinical phenotype in such patients. We describe 6 unreported individuals and provide updated information on an additional previously reported individual with heterozygous de novo missense variants in YWHAG. We describe a syndromal phenotype, report 5 novel, and a recurrent p.Arg132Cys YWHAG variant and compare developmental trajectory and treatment strategies in this cohort. We provide further evidence of causality in YWHAG variants. WES was performed in five patients via Deciphering Developmental Disorders Study and the remaining two were identified via Genematcher and AnnEX databases. De novo variants identified from exome data were validated using Sanger sequencing. Seven out of seven patients in the cohort have de novo, heterozygous missense variants in YWHAG including 2/7 patients with a recurrent c.394C > T, p.Arg132Cys variant; 1/7 has a second, pathogenic variant in STAG1. Characteristic features included: early-onset seizures, predominantly generalized tonic-clonic and absence type (7/7) with good response to standard anti-epileptic medications; moderate DD; Intellectual Disability (ID) (5/7) and Autism Spectrum Disorder (3/7). De novo YWHAG missense variants cause EE, characterized by early-onset epilepsy, ID and DD, supporting the hypothesis that YWHAG loss-of-function causes a neurological phenotype. Although the exact mechanism of disease resulting from alterations in YWHAG is not fully known, it is possible that haploinsufficiency of YWHAG in developing cerebral cortex may lead to abnormal neuronal migration resulting in DEE.
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http://dx.doi.org/10.1002/ajmg.a.61483DOI Listing
April 2020

Autosomal dominant inheritance in a recently described ZMIZ1-related neurodevelopmental disorder: Case report of siblings and an affected parent.

Am J Med Genet A 2020 03 12;182(3):548-552. Epub 2019 Dec 12.

Division of Clinical and Translational Genetics, Department of Human Genetics, Miller School of Medicine, University of Miami, Coral Gables, Florida.

ZMIZ1, zinc finger MIZ-domain containing 1, has recently been described in association with syndromic intellectual disability in which the primary phenotypic features include intellectual disability/developmental delay, seizures, hearing loss, behavioral issues, failure to thrive, and various congenital malformations. Most reported cases have been found to result from de novo mutations except for one set of three siblings in which parental testing could not be performed. With informed consent from the family, we report on a father and his two sons demonstrating autosomal dominant inheritance of a novel pathogenic ZMIZ1 variant, c.1310delC (p.Pro437ArgfsX84), causing this recently described neurodevelopmental syndrome. While they all show syndromic findings along with short stature and intellectual disability, only one child had sensorineural hearing loss. Moreover, severity of intellectual disability and eyelid ptosis were variable among the affected members. Our report demonstrates that phenotypic features of ZMIZ1-related neurodevelopmental syndrome are variable even within the same family and that parental testing to identify a mildly affected parent is needed.
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http://dx.doi.org/10.1002/ajmg.a.61446DOI Listing
March 2020

Loss of Oxidation Resistance 1, OXR1, Is Associated with an Autosomal-Recessive Neurological Disease with Cerebellar Atrophy and Lysosomal Dysfunction.

Am J Hum Genet 2019 12 27;105(6):1237-1253. Epub 2019 Nov 27.

Centre Hospitalier Universitaire Saint-Justine Research Center, CHU Sainte-Justine, Montreal, QC H3T 1J4, Canada. Electronic address:

We report an early-onset autosomal-recessive neurological disease with cerebellar atrophy and lysosomal dysfunction. We identified bi-allelic loss-of-function (LoF) variants in Oxidative Resistance 1 (OXR1) in five individuals from three families; these individuals presented with a history of severe global developmental delay, current intellectual disability, language delay, cerebellar atrophy, and seizures. While OXR1 is known to play a role in oxidative stress resistance, its molecular functions are not well established. OXR1 contains three conserved domains: LysM, GRAM, and TLDc. The gene encodes at least six transcripts, including some that only consist of the C-terminal TLDc domain. We utilized Drosophila to assess the phenotypes associated with loss of mustard (mtd), the fly homolog of OXR1. Strong LoF mutants exhibit late pupal lethality or pupal eclosion defects. Interestingly, although mtd encodes 26 transcripts, severe LoF and null mutations can be rescued by a single short human OXR1 cDNA that only contains the TLDc domain. Similar rescue is observed with the TLDc domain of NCOA7, another human homolog of mtd. Loss of mtd in neurons leads to massive cell loss, early death, and an accumulation of aberrant lysosomal structures, similar to what we observe in fibroblasts of affected individuals. Our data indicate that mtd and OXR1 are required for proper lysosomal function; this is consistent with observations that NCOA7 is required for lysosomal acidification.
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http://dx.doi.org/10.1016/j.ajhg.2019.11.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6904826PMC
December 2019

Prospective, phenotype-driven selection of critically ill neonates for rapid exome sequencing is associated with high diagnostic yield.

Genet Med 2020 04 29;22(4):736-744. Epub 2019 Nov 29.

Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA.

Purpose: To investigate the impact of rapid-turnaround exome sequencing in critically ill neonates using phenotype-based subject selection criteria.

Methods: Intensive care unit babies aged <6 months with hypotonia, seizures, a complex metabolic phenotype, and/or multiple congenital malformations were prospectively enrolled for rapid (<7 day) trio-based exome sequencing. Genomic variants relevant to the presenting phenotype were returned to the medical team.

Results: A genetic diagnosis was attained in 29 of 50 (58%) sequenced cases. Twenty-seven (54%) patients received a molecular diagnosis involving known disease genes; two additional cases (4%) were solved with pathogenic variants found in novel disease genes. In 24 of the solved cases, diagnosis had impact on patient management and/or family members. Management changes included shift to palliative care, medication changes, involvement of additional specialties, and the consideration of new experimental therapies.

Conclusion: Phenotype-based patient selection is effective at identifying critically ill neonates with a high likelihood of receiving a molecular diagnosis via rapid-turnaround exome sequencing, leading to faster and more accurate diagnoses, reducing unnecessary testing and procedures, and informing medical care.
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http://dx.doi.org/10.1038/s41436-019-0708-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7127968PMC
April 2020

Truncating variants in UBAP1 associated with childhood-onset nonsyndromic hereditary spastic paraplegia.

Hum Mutat 2020 03 25;41(3):632-640. Epub 2019 Nov 25.

Department of Molecular and Human Genetics, Faculty of Medicine, Baylor College of Medicine, Houston, Texas.

Hereditary spastic paraplegia (HSP) is a group of disorders with predominant symptoms of lower-extremity weakness and spasticity. Despite the delineation of numerous genetic causes of HSP, a significant portion of individuals with HSP remain molecularly undiagnosed. Through exome sequencing, we identified five unrelated families with childhood-onset nonsyndromic HSP, all presenting with progressive spastic gait, leg clonus, and toe walking starting from 7 to 8 years old. A recurrent two-base pair deletion (c.426_427delGA, p.K143Sfs*15) in the UBAP1 gene was found in four families, and a similar variant (c.475_476delTT, p.F159*) was detected in a fifth family. The variant was confirmed to be de novo in two families and inherited from an affected parent in two other families. RNA studies performed in lymphocytes from one patient with the de novo c.426_427delGA variant demonstrated escape of nonsense-mediated decay of the UBAP1 mutant transcript, suggesting the generation of a truncated protein. Both variants identified in this study are predicted to result in truncated proteins losing the capacity of binding to ubiquitinated proteins, hence appearing to exhibit a dominant-negative effect on the normal function of the endosome-specific endosomal sorting complexes required for the transport-I complex.
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http://dx.doi.org/10.1002/humu.23950DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8207780PMC
March 2020

Disruptive mutations in TANC2 define a neurodevelopmental syndrome associated with psychiatric disorders.

Nat Commun 2019 10 15;10(1):4679. Epub 2019 Oct 15.

Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.

Postsynaptic density (PSD) proteins have been implicated in the pathophysiology of neurodevelopmental and psychiatric disorders. Here, we present detailed clinical and genetic data for 20 patients with likely gene-disrupting mutations in TANC2-whose protein product interacts with multiple PSD proteins. Pediatric patients with disruptive mutations present with autism, intellectual disability, and delayed language and motor development. In addition to a variable degree of epilepsy and facial dysmorphism, we observe a pattern of more complex psychiatric dysfunction or behavioral problems in adult probands or carrier parents. Although this observation requires replication to establish statistical significance, it also suggests that mutations in this gene are associated with a variety of neuropsychiatric disorders consistent with its postsynaptic function. We find that TANC2 is expressed broadly in the human developing brain, especially in excitatory neurons and glial cells, but shows a more restricted pattern in Drosophila glial cells where its disruption affects behavioral outcomes.
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http://dx.doi.org/10.1038/s41467-019-12435-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6794285PMC
October 2019

Clinical utility of exome sequencing in infantile heart failure.

Genet Med 2020 02 17;22(2):423-426. Epub 2019 Sep 17.

Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA.

Purpose: Pediatric cardiomyopathy is rare, has a broad differential diagnosis, results in high morbidity and mortality, and has suboptimal diagnostic yield using next-generation sequencing panels. Exome sequencing has reported diagnostic yields ranging from 30% to 57% for neonates in intensive care units. We aimed to characterize the clinical utility of exome sequencing in infantile heart failure.

Methods: Infants diagnosed with acute heart failure prior to 1 year old over a period of 34 months at a large tertiary children's hospital were recruited. Demographic and diagnostic information was obtained from medical records. Fifteen eligible patients were enrolled.

Results: Dilated cardiomyopathy was the predominant cardiac diagnosis, seen in 60% of patients. A molecular diagnosis was identified in 66.7% of patients (10/15). Of those diagnoses, 70% would not have been detected using multigene next-generation sequencing panels focused on cardiomyopathy or arrhythmia disease genes. Genetic testing changed medical decision-making in 53% of all cases and 80% of positive cases, and was especially beneficial when testing was expedited.

Conclusion: Given the broad differential diagnosis and critical status of infants with heart failure, rapid exome sequencing provides timely diagnoses, changes medical management, and should be the first-tier molecular test.
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http://dx.doi.org/10.1038/s41436-019-0654-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7339672PMC
February 2020
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