Publications by authors named "Denise Horn"

137 Publications

Germline Mutations Including the Rare Pathogenic Variant c.3206delC in the Gene Cause Ataxia Teleangiectasia-Associated Primary Central Nervous System Lymphoma.

Children (Basel) 2021 Jun 2;8(6). Epub 2021 Jun 2.

Department of Pediatric Hematology and Oncology, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany.

We here report the case of a 2-year-old patient with a primary central nervous system lymphoma of B-cell origin. Due to their past medical history of repeated respiratory tract infections and the marked chemotherapy-associated toxicity and infectious comorbidity, we suspected that the patient also suffered from an inherited immune deficiency disorder. Despite the lack of classical pathognomonic symptoms for ataxia teleangiectasia and missing evidence for a cancer predisposition syndrome in the family, genetic testing identified biallelic germline mutations, including the rare pathogenic variant c.3206delC (p.Pro1069Leufs*2), in the ataxia telangiectasia-mutated () gene. The case highlights the importance of searching for immune deficiency disorders associated with primary central nervous system lymphoma before treatment initiation and the urgent need to develop novel treatment strategies for cancer patients with underlying immunodeficiency syndromes.
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http://dx.doi.org/10.3390/children8060469DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8229184PMC
June 2021

Genome sequencing in families with congenital limb malformations.

Hum Genet 2021 Aug 22;140(8):1229-1239. Epub 2021 Jun 22.

Institute of Medical Genetics and Human Genetics, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.

The extensive clinical and genetic heterogeneity of congenital limb malformation calls for comprehensive genome-wide analysis of genetic variation. Genome sequencing (GS) has the potential to identify all genetic variants. Here we aim to determine the diagnostic potential of GS as a comprehensive one-test-for-all strategy in a cohort of undiagnosed patients with congenital limb malformations. We collected 69 cases (64 trios, 1 duo, 5 singletons) with congenital limb malformations with no molecular diagnosis after standard clinical genetic testing and performed genome sequencing. We also developed a framework to identify potential noncoding pathogenic variants. We identified likely pathogenic/disease-associated variants in 12 cases (17.4%) including four in known disease genes, and one repeat expansion in HOXD13. In three unrelated cases with ectrodactyly, we identified likely pathogenic variants in UBA2, establishing it as a novel disease gene. In addition, we found two complex structural variants (3%). We also identified likely causative variants in three novel high confidence candidate genes. We were not able to identify any noncoding variants. GS is a powerful strategy to identify all types of genomic variants associated with congenital limb malformation, including repeat expansions and complex structural variants missed by standard diagnostic approaches. In this cohort, no causative noncoding SNVs could be identified.
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http://dx.doi.org/10.1007/s00439-021-02295-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8263393PMC
August 2021

ANKRD11 variants: KBG syndrome and beyond.

Clin Genet 2021 Aug 14;100(2):187-200. Epub 2021 May 14.

Centro Fondazione Mariani per il Bambino Fragile ASST-Lariana Sant'Anna Hospital, Department of Pediatrics, San Fermo della Battaglia (Como), Italy.

Mutations affecting the transcriptional regulator Ankyrin Repeat Domain 11 (ANKRD11) are mainly associated with the multisystem developmental disorder known as KBG syndrome, but have also been identified in individuals with Cornelia de Lange syndrome (CdLS) and other developmental disorders caused by variants affecting different chromatin regulators. The extensive functional overlap of these proteins results in shared phenotypical features, which complicate the assessment of the clinical diagnosis. Additionally, re-evaluation of individuals at a later age occasionally reveals that the initial phenotype has evolved toward clinical features more reminiscent of a developmental disorder different from the one that was initially diagnosed. For this reason, variants in ANKRD11 can be ascribed to a broader class of disorders that fall within the category of the so-called chromatinopathies. In this work, we report on the clinical characterization of 23 individuals with variants in ANKRD11. The subjects present primarily with developmental delay, intellectual disability and dysmorphic features, and all but two received an initial clinical diagnosis of either KBG syndrome or CdLS. The number and the severity of the clinical signs are overlapping but variable and result in a broad spectrum of phenotypes, which could be partially accounted for by the presence of additional molecular diagnoses and distinct pathogenic mechanisms.
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http://dx.doi.org/10.1111/cge.13977DOI Listing
August 2021

CDK19-related disorder results from both loss-of-function and gain-of-function de novo missense variants.

Genet Med 2021 06 25;23(6):1050-1057. Epub 2021 Jan 25.

Laboratory of Gene Regulation, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.

Purpose: To expand the recent description of a new neurodevelopmental syndrome related to alterations in CDK19.

Methods: Individuals were identified through international collaboration. Functional studies included autophosphorylation assays for CDK19 Gly28Arg and Tyr32His variants and in vivo zebrafish assays of the CDK19 and CDK19.

Results: We describe 11 unrelated individuals (age range: 9 months to 14 years) with de novo missense variants mapped to the kinase domain of CDK19, including two recurrent changes at residues Tyr32 and Gly28. In vitro autophosphorylation and substrate phosphorylation assays revealed that kinase activity of protein was lower for p.Gly28Arg and higher for p.Tyr32His substitutions compared with that of the wild-type protein. Injection of CDK19 messenger RNA (mRNA) with either the Tyr32His or the Gly28Arg variants using in vivo zebrafish model significantly increased fraction of embryos with morphological abnormalities. Overall, the phenotype of the now 14 individuals with CDK19-related disorder includes universal developmental delay and facial dysmorphism, hypotonia (79%), seizures (64%), ophthalmologic anomalies (64%), and autism/autistic traits (56%).

Conclusion: CDK19 de novo missense variants are responsible for a novel neurodevelopmental disorder. Both kinase assay and zebrafish experiments showed that the pathogenetic mechanism may be more diverse than previously thought.
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http://dx.doi.org/10.1038/s41436-020-01091-9DOI Listing
June 2021

Biallelic truncating variants in MAPKAPK5 cause a new developmental disorder involving neurological, cardiac, and facial anomalies combined with synpolydactyly.

Genet Med 2021 04 13;23(4):679-688. Epub 2021 Jan 13.

Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain.

Purpose: This study aimed to identify the genetic cause of a new multiple congenital anomalies syndrome observed in three individuals from two unrelated families.

Methods: Clinical assessment was conducted prenatally and at different postnatal stages. Genetic studies included exome sequencing (ES) combined with single-nucleotide polymorphism (SNP) array based homozygosity mapping and trio ES. Dermal fibroblasts were used for functional assays.

Results: A clinically recognizable syndrome characterized by severe developmental delay, variable brain anomalies, congenital heart defects, dysmorphic facial features, and a distinctive type of synpolydactyly with an additional hypoplastic digit between the fourth and fifth digits of hands and/or feet was identified. Additional features included eye abnormalities, hearing impairment, and electroencephalogram anomalies. ES detected different homozygous truncating variants in MAPKAPK5 in both families. Patient-derived cells showed no expression of MAPKAPK5 protein isoforms and reduced levels of the MAPKAPK5-interacting protein ERK3. F-actin recovery after latrunculin B treatment was found to be less efficient in patient-derived fibroblasts than in control cells, supporting a role of MAPKAPK5 in F-actin polymerization.

Conclusion: Our data indicate that loss-of-function variants in MAPKAPK5 result in a severe developmental disorder and reveal a major role of this gene in human brain, heart, and limb development.
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http://dx.doi.org/10.1038/s41436-020-01052-2DOI Listing
April 2021

A CRISPR-Cas9-engineered mouse model for GPI-anchor deficiency mirrors human phenotypes and exhibits hippocampal synaptic dysfunctions.

Proc Natl Acad Sci U S A 2021 01;118(2)

Institute for Genomic Statistics and Bioinformatics, University of Bonn, 53127 Bonn, Germany;

Pathogenic germline mutations in lead to glycosylphosphatidylinositol biosynthesis deficiency (GPIBD). Individuals with pathogenic biallelic mutations in genes of the glycosylphosphatidylinositol (GPI)-anchor pathway exhibit cognitive impairments, motor delay, and often epilepsy. Thus far, the pathophysiology underlying the disease remains unclear, and suitable rodent models that mirror all symptoms observed in human patients have not been available. Therefore, we used CRISPR-Cas9 to introduce the most prevalent hypomorphic missense mutation in European patients, :c.1022C > A (p.A341E), at a site that is conserved in mice. Mirroring the human pathology, mutant mice exhibited deficits in motor coordination, cognitive impairments, and alterations in sociability and sleep patterns, as well as increased seizure susceptibility. Furthermore, immunohistochemistry revealed reduced synaptophysin immunoreactivity in mice, and electrophysiology recordings showed decreased hippocampal synaptic transmission that could underlie impaired memory formation. In single-cell RNA sequencing, -hippocampal cells exhibited changes in gene expression, most prominently in a subtype of microglia and subicular neurons. A significant reduction in transcript levels in several cell clusters suggested a link to the signaling pathway of GPI-anchored ephrins. We also observed elevated levels of transcripts, which might affect histamine metabolism with consequences for circadian rhythm. This mouse model will not only open the doors to further investigation into the pathophysiology of GPIBD, but will also deepen our understanding of the role of GPI-anchor-related pathways in brain development.
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http://dx.doi.org/10.1073/pnas.2014481118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7812744PMC
January 2021

Variants in the SK2 channel gene (KCNN2) lead to dominant neurodevelopmental movement disorders.

Brain 2020 12;143(12):3564-3573

Institute of Human Genetics, University Hospital Magdeburg, Magdeburg, Germany.

KCNN2 encodes the small conductance calcium-activated potassium channel 2 (SK2). Rodent models with spontaneous Kcnn2 mutations show abnormal gait and locomotor activity, tremor and memory deficits, but human disorders related to KCNN2 variants are largely unknown. Using exome sequencing, we identified a de novo KCNN2 frameshift deletion in a patient with learning disabilities, cerebellar ataxia and white matter abnormalities on brain MRI. This discovery prompted us to collect data from nine additional patients with de novo KCNN2 variants (one nonsense, one splice site, six missense variants and one in-frame deletion) and one family with a missense variant inherited from the affected mother. We investigated the functional impact of six selected variants on SK2 channel function using the patch-clamp technique. All variants tested but one, which was reclassified to uncertain significance, led to a loss-of-function of SK2 channels. Patients with KCNN2 variants had motor and language developmental delay, intellectual disability often associated with early-onset movement disorders comprising cerebellar ataxia and/or extrapyramidal symptoms. Altogether, our findings provide evidence that heterozygous variants, likely causing a haploinsufficiency of the KCNN2 gene, lead to novel autosomal dominant neurodevelopmental movement disorders mirroring phenotypes previously described in rodents.
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http://dx.doi.org/10.1093/brain/awaa346DOI Listing
December 2020

Efficiency of Computer-Aided Facial Phenotyping (DeepGestalt) in Individuals With and Without a Genetic Syndrome: Diagnostic Accuracy Study.

J Med Internet Res 2020 10 22;22(10):e19263. Epub 2020 Oct 22.

Institute of Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.

Background: Collectively, an estimated 5% of the population have a genetic disease. Many of them feature characteristics that can be detected by facial phenotyping. Face2Gene CLINIC is an online app for facial phenotyping of patients with genetic syndromes. DeepGestalt, the neural network driving Face2Gene, automatically prioritizes syndrome suggestions based on ordinary patient photographs, potentially improving the diagnostic process. Hitherto, studies on DeepGestalt's quality highlighted its sensitivity in syndromic patients. However, determining the accuracy of a diagnostic methodology also requires testing of negative controls.

Objective: The aim of this study was to evaluate DeepGestalt's accuracy with photos of individuals with and without a genetic syndrome. Moreover, we aimed to propose a machine learning-based framework for the automated differentiation of DeepGestalt's output on such images.

Methods: Frontal facial images of individuals with a diagnosis of a genetic syndrome (established clinically or molecularly) from a convenience sample were reanalyzed. Each photo was matched by age, sex, and ethnicity to a picture featuring an individual without a genetic syndrome. Absence of a facial gestalt suggestive of a genetic syndrome was determined by physicians working in medical genetics. Photos were selected from online reports or were taken by us for the purpose of this study. Facial phenotype was analyzed by DeepGestalt version 19.1.7, accessed via Face2Gene CLINIC. Furthermore, we designed linear support vector machines (SVMs) using Python 3.7 to automatically differentiate between the 2 classes of photographs based on DeepGestalt's result lists.

Results: We included photos of 323 patients diagnosed with 17 different genetic syndromes and matched those with an equal number of facial images without a genetic syndrome, analyzing a total of 646 pictures. We confirm DeepGestalt's high sensitivity (top 10 sensitivity: 295/323, 91%). DeepGestalt's syndrome suggestions in individuals without a craniofacially dysmorphic syndrome followed a nonrandom distribution. A total of 17 syndromes appeared in the top 30 suggestions of more than 50% of nondysmorphic images. DeepGestalt's top scores differed between the syndromic and control images (area under the receiver operating characteristic [AUROC] curve 0.72, 95% CI 0.68-0.76; P<.001). A linear SVM running on DeepGestalt's result vectors showed stronger differences (AUROC 0.89, 95% CI 0.87-0.92; P<.001).

Conclusions: DeepGestalt fairly separates images of individuals with and without a genetic syndrome. This separation can be significantly improved by SVMs running on top of DeepGestalt, thus supporting the diagnostic process of patients with a genetic syndrome. Our findings facilitate the critical interpretation of DeepGestalt's results and may help enhance it and similar computer-aided facial phenotyping tools.
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http://dx.doi.org/10.2196/19263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7644377PMC
October 2020

Genotypic diversity and phenotypic spectrum of infantile liver failure syndrome type 1 due to variants in LARS1.

Genet Med 2020 11 23;22(11):1863-1873. Epub 2020 Jul 23.

Division of Neuropediatrics and Pediatric Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany.

Purpose: Biallelic variants in LARS1, coding for the cytosolic leucyl-tRNA synthetase, cause infantile liver failure syndrome 1 (ILFS1). Since its description in 2012, there has been no systematic analysis of the clinical spectrum and genetic findings.

Methods: Individuals with biallelic variants in LARS1 were included through an international, multicenter collaboration including novel and previously published patients. Clinical variables were analyzed and functional studies were performed in patient-derived fibroblasts.

Results: Twenty-five individuals from 15 families were ascertained including 12 novel patients with eight previously unreported variants. The most prominent clinical findings are recurrent elevation of liver transaminases up to liver failure and encephalopathic episodes, both triggered by febrile illness. Magnetic resonance image (MRI) changes during an encephalopathic episode can be consistent with metabolic stroke. Furthermore, growth retardation, microcytic anemia, neurodevelopmental delay, muscular hypotonia, and infection-related seizures are prevalent. Aminoacylation activity is significantly decreased in all patient cells studied upon temperature elevation in vitro.

Conclusion: ILFS1 is characterized by recurrent elevation of liver transaminases up to liver failure in conjunction with abnormalities of growth, blood, nervous system, and musculature. Encephalopathic episodes with seizures can occur independently from liver crises and may present with metabolic stroke.
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http://dx.doi.org/10.1038/s41436-020-0904-4DOI Listing
November 2020

An intronic splice site alteration in combination with a large deletion affecting VPS13B (COH1) causes Cohen syndrome.

Eur J Med Genet 2020 Sep 4;63(9):103973. Epub 2020 Jun 4.

Charité - Universitätsmedizin Berlin, Institut für Medizinische Genetik und Humangenetik, Augustenburger Platz 1, 13353, Berlin, Germany. Electronic address:

Cohen syndrome (CS) is a rare, autosomal recessive disorder characterized by intellectual disability, postnatal microcephaly, facial abnormalities, abnormal truncal fat distribution, myopia, and pigmentary retinopathy. It is often considered an underdiagnosed condition, especially in children with developmental delay and intellectual disability. Here we report on four individuals from a large Jordanian family clinically diagnosed with CS. Using Trio Exome Sequencing (Trio-WES) and MLPA analyses we identified a maternally inherited novel intronic nucleotide substitution c.3446-23T>G leading to the activation of a cryptic splice site and a paternally inherited multi-exon deletion in VPS13B (previously termed COH1) in the index patient. Expression analysis showed a strong decrease of VPS13B mRNA levels and direct sequencing of cDNA confirmed splicing at a cryptic upstream splice acceptor site, resulting in the inclusion of 22 intronic bases. This extension results in a frameshift and a premature stop of translation (p.Gly1149Valfs*9). Segregation analysis revealed that three affected maternal cousins were homozygous for the intronic splice site variant. Our data show causality of both alterations and strongly suggest the expansion of the diagnostic strategy to search for intronic splice variants in molecularly unconfirmed patients affected by CS.
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http://dx.doi.org/10.1016/j.ejmg.2020.103973DOI Listing
September 2020

Kagami-Ogata syndrome: an important differential diagnosis to Beckwith-Wiedemann syndrome.

J Clin Ultrasound 2020 May 28;48(4):240-243. Epub 2020 Jan 28.

Klinik für Geburtsmedizin, Charité - Universitätsmedizin, Berlin, Germany.

We report the case of a fetus with sonographic characteristics of Beckwith-Wiedemann syndrome (BWS). A 30-year-old gravida 2 para 1 was referred to our fetal medicine unit with an omphalocele. Fetal macrosomia, organomegaly, and polyhydramnios but no macroglossia were detected and BWS was suspected. Genetic testing for BWS did not confirm the suspected diagnosis as the karyotype was normal. Symptomatic polyhydramnios led to repeated amnioreductions. At 35 + 5 weeks of gestation, a female neonate of 3660 g was delivered with APGAR scores of 6/7/8, after 1/5/10 min, respectively. The abnormal shape of the thorax, facial dysmorphism, need for ventilation, and generalized muscular hypotonia led to the suspicion of Kagami-Ogata syndrome (KOS), which was confirmed by genetic testing. KOS in our patient was caused by a large deletion in the MEG3-region on chromosome 14q32 affecting the maternal allele. In this report, we highlight the notion that when sonographic signs suggestive of BWS such as macrosomia, polyhydramnios, and omphalocele are present and genetic testing does not confirm the suspected diagnosis, KOS should be tested for.
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http://dx.doi.org/10.1002/jcu.22815DOI Listing
May 2020

MN1 C-terminal truncation syndrome is a novel neurodevelopmental and craniofacial disorder with partial rhombencephalosynapsis.

Brain 2020 01;143(1):55-68

GeneDx, Gaithersburg, MD, USA.

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3' region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.
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http://dx.doi.org/10.1093/brain/awz379DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7962909PMC
January 2020

Haploinsufficiency of the Notch Ligand DLL1 Causes Variable Neurodevelopmental Disorders.

Am J Hum Genet 2019 09 25;105(3):631-639. Epub 2019 Jul 25.

GeneDx, Gaithersburg, MD 20877, USA.

Notch signaling is an established developmental pathway for brain morphogenesis. Given that Delta-like 1 (DLL1) is a ligand for the Notch receptor and that a few individuals with developmental delay, intellectual disability, and brain malformations have microdeletions encompassing DLL1, we hypothesized that insufficiency of DLL1 causes a human neurodevelopmental disorder. We performed exome sequencing in individuals with neurodevelopmental disorders. The cohort was identified using known Matchmaker Exchange nodes such as GeneMatcher. This method identified 15 individuals from 12 unrelated families with heterozygous pathogenic DLL1 variants (nonsense, missense, splice site, and one whole gene deletion). The most common features in our cohort were intellectual disability, autism spectrum disorder, seizures, variable brain malformations, muscular hypotonia, and scoliosis. We did not identify an obvious genotype-phenotype correlation. Analysis of one splice site variant showed an in-frame insertion of 12 bp. In conclusion, heterozygous DLL1 pathogenic variants cause a variable neurodevelopmental phenotype and multi-systemic features. The clinical and molecular data support haploinsufficiency as a mechanism for the pathogenesis of this DLL1-related disorder and affirm the importance of DLL1 in human brain development.
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http://dx.doi.org/10.1016/j.ajhg.2019.07.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6731356PMC
September 2019

Mutations in PIGU Impair the Function of the GPI Transamidase Complex, Causing Severe Intellectual Disability, Epilepsy, and Brain Anomalies.

Am J Hum Genet 2019 08 25;105(2):395-402. Epub 2019 Jul 25.

Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany.

The glycosylphosphatidylinositol (GPI) anchor links over 150 proteins to the cell surface and is present on every cell type. Many of these proteins play crucial roles in neuronal development and function. Mutations in 18 of the 29 genes implicated in the biosynthesis of the GPI anchor have been identified as the cause of GPI biosynthesis deficiencies (GPIBDs) in humans. GPIBDs are associated with intellectual disability and seizures as their cardinal features. An essential component of the GPI transamidase complex is PIGU, along with PIGK, PIGS, PIGT, and GPAA1, all of which link GPI-anchored proteins (GPI-APs) onto the GPI anchor in the endoplasmic reticulum (ER). Here, we report two homozygous missense mutations (c.209T>A [p.Ile70Lys] and c.1149C>A [p.Asn383Lys]) in five individuals from three unrelated families. All individuals presented with global developmental delay, severe-to-profound intellectual disability, muscular hypotonia, seizures, brain anomalies, scoliosis, and mild facial dysmorphism. Using multicolor flow cytometry, we determined a characteristic profile for GPI transamidase deficiency. On granulocytes this profile consisted of reduced cell-surface expression of fluorescein-labeled proaerolysin (FLAER), CD16, and CD24, but not of CD55 and CD59; additionally, B cells showed an increased expression of free GPI anchors determined by T5 antibody. Moreover, computer-assisted facial analysis of different GPIBDs revealed a characteristic facial gestalt shared among individuals with mutations in PIGU and GPAA1. Our findings improve our understanding of the role of the GPI transamidase complex in the development of nervous and skeletal systems and expand the clinical spectrum of disorders belonging to the group of inherited GPI-anchor deficiencies.
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http://dx.doi.org/10.1016/j.ajhg.2019.06.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6698879PMC
August 2019

Differentiation of MISSLA and Fanconi anaemia by computer-aided image analysis and presentation of two novel MISSLA siblings.

Eur J Hum Genet 2019 12 18;27(12):1827-1835. Epub 2019 Jul 18.

Institute of Medical Genetics and Human Genetics, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.

Variants in DONSON were recently identified as the cause of microcephaly, short stature, and limb abnormalities syndrome (MISSLA). The clinical spectra of MISSLA and Fanconi anaemia (FA) strongly overlap. For that reason, some MISSLA patients have been clinically diagnosed with FA. Here, we present the clinical data of siblings with MISSLA featuring a novel DONSON variant and summarize the current literature on MISSLA. Additionally, we perform computer-aided image analysis using the DeepGestalt technology to test how distinct the facial features of MISSLA and FA patients are. We show that MISSLA has a specific facial gestalt. Notably, we find that also FA patients feature facial characteristics recognizable by computer-aided image analysis. We conclude that computer-assisted image analysis improves diagnostic precision in both MISSLA and FA.
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http://dx.doi.org/10.1038/s41431-019-0469-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6871132PMC
December 2019

Primary Hypertrophic Osteoarthropathy Mimicking Juvenile Idiopathic Arthritis: A Novel SLCO2A1 Mutation and Imaging Findings.

Cytogenet Genome Res 2019 15;158(3):126-132. Epub 2019 Jun 15.

Primary hypertrophic osteoarthropathy (PHO), also known as pachydermoperiostosis, is a rare, multisystemic, autosomal recessive condition typically presenting with digital clubbing, osteoarthropathy, and various skin manifestations. Radiographs show distinctive periosteal reaction and thickening along the long bones. PHO is caused by homozygous mutations in the HPGD gene in chromosome 4q34.1 or the SLCO2A1 gene in 3q22.1q22.2. Here, we report on a 20-year-old male with enlarged and swollen joints with arthralgia, palmoplantar hyperhidrosis, and large hands and feet with marked digital clubbing. We also present radiographic, MRI, and ultrasonographic features of the case. These clinical and imaging findings were compatible with the diagnosis of PHO, and a novel homozygous mutation, c.576C>G, p.Ile192Met, was found in SLCO2A1.
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http://dx.doi.org/10.1159/000500988DOI Listing
September 2019

PEDIA: prioritization of exome data by image analysis.

Genet Med 2019 12 5;21(12):2807-2814. Epub 2019 Jun 5.

National Research and Applied Medicine Centre 'Mother and Child'', Minsk, Belarus.

Purpose: Phenotype information is crucial for the interpretation of genomic variants. So far it has only been accessible for bioinformatics workflows after encoding into clinical terms by expert dysmorphologists.

Methods: Here, we introduce an approach driven by artificial intelligence that uses portrait photographs for the interpretation of clinical exome data. We measured the value added by computer-assisted image analysis to the diagnostic yield on a cohort consisting of 679 individuals with 105 different monogenic disorders. For each case in the cohort we compiled frontal photos, clinical features, and the disease-causing variants, and simulated multiple exomes of different ethnic backgrounds.

Results: The additional use of similarity scores from computer-assisted analysis of frontal photos improved the top 1 accuracy rate by more than 20-89% and the top 10 accuracy rate by more than 5-99% for the disease-causing gene.

Conclusion: Image analysis by deep-learning algorithms can be used to quantify the phenotypic similarity (PP4 criterion of the American College of Medical Genetics and Genomics guidelines) and to advance the performance of bioinformatics pipelines for exome analysis.
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http://dx.doi.org/10.1038/s41436-019-0566-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6892739PMC
December 2019

Breast cancer risk in BRCA1/2 mutation carriers and noncarriers under prospective intensified surveillance.

Int J Cancer 2020 02 22;146(4):999-1009. Epub 2019 May 22.

Department of Obstetrics and Gynecology, Würzburg University Hospital, Würzburg, Germany.

Comparably little is known about breast cancer (BC) risks in women from families tested negative for BRCA1/2 mutations despite an indicative family history, as opposed to BRCA1/2 mutation carriers. We determined the age-dependent risks of first and contralateral breast cancer (FBC, CBC) both in noncarriers and carriers of BRCA1/2 mutations, who participated in an intensified breast imaging surveillance program. The study was conducted between January 1, 2005, and September 30, 2017, at 12 university centers of the German Consortium for Hereditary Breast and Ovarian Cancer. Two cohorts were prospectively followed up for incident FBC (n = 4,380; 16,398 person-years [PY], median baseline age: 39 years) and CBC (n = 2,993; 10,090 PY, median baseline age: 42 years). Cumulative FBC risk at age 60 was 61.8% (95% CI 52.8-70.9%) for BRCA1 mutation carriers, 43.2% (95% CI 32.1-56.3%) for BRCA2 mutation carriers and 15.7% (95% CI 11.9-20.4%) for noncarriers. FBC risks were significantly higher than in the general population, with incidence rate ratios of 23.9 (95% CI 18.9-29.8) for BRCA1 mutation carriers, 13.5 (95% CI 9.2-19.1) for BRCA2 mutation carriers and 4.9 (95% CI 3.8-6.3) for BRCA1/2 noncarriers. Cumulative CBC risk 10 years after FBC was 25.1% (95% CI 19.6-31.9%) for BRCA1 mutation carriers, 6.6% (95% CI 3.4-12.5%) for BRCA2 mutation carriers and 3.6% (95% CI 2.2-5.7%) for noncarriers. CBC risk in noncarriers was similar to women with unilateral BC from the general population. Further studies are needed to confirm whether less intensified surveillance is justified in women from BRCA1/2 negative families with elevated risk.
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http://dx.doi.org/10.1002/ijc.32396DOI Listing
February 2020

SOPH syndrome in three affected individuals showing similarities with progeroid cutis laxa conditions in early infancy.

J Hum Genet 2019 Jul 24;64(7):609-616. Epub 2019 Apr 24.

Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

Individuals affected with autosomal recessive cutis laxa type 2B and 3 usually show translucent skin with visible veins and abnormal elastic fibers, intrauterine and/or postnatal growth restriction and a typical triangular facial gestalt. Here we describe three unrelated individuals in whom such a cutis laxa syndrome was suspected, especially after electron microscopy revealed immature and less dense dermal elastic fibers in one of them. However, one of these children also displayed optic atrophy and two hypogammaglobulinemia. All had elevated liver enzymes and acute liver failure during febrile episodes leading to early demise in two of them. The only surviving patient had been treated with immunoglobulins. Through exome sequencing we identified mutations in NBAS, coding for a protein involved in Golgi-to-ER transport. NBAS deficiency causes several rare conditions ranging from isolated recurrent acute liver failure to a multisystem disorder mainly characterized by short stature, optic nerve atrophy and Pelger-Huët anomaly (SOPH). Since we subsequently verified Pelger-Huët anomaly in two of the patients the diagnosis SOPH syndrome was unequivocally proven. Our data show that SOPH syndrome can be regarded as a differential diagnosis for the progeroid forms of cutis laxa in early infancy and that possibly treatment of the hypogammaglobulinemia can be of high relevance for the prognosis.
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http://dx.doi.org/10.1038/s10038-019-0602-8DOI Listing
July 2019

Variants in KIAA0825 underlie autosomal recessive postaxial polydactyly.

Hum Genet 2019 Jun 13;138(6):593-600. Epub 2019 Apr 13.

Department of Molecular and Human Genetics, Center for Statistical Genetics, Baylor College of Medicine, 1 Baylor Plaza 700D, Houston, TX, 77030, USA.

Postaxial polydactyly (PAP) is a common limb malformation that often leads to cosmetic and functional complications. Molecular evaluation of polydactyly can serve as a tool to elucidate genetic and signaling pathways that regulate limb development, specifically, the anterior-posterior specification of the limb. To date, only five genes have been identified for nonsyndromic PAP: FAM92A, GLI1, GLI3, IQCE and ZNF141. In this study, two Pakistani multiplex consanguineous families with autosomal recessive nonsyndromic PAP were clinically and molecularly evaluated. From both pedigrees, a DNA sample from an affected member underwent exome sequencing. In each family, we identified a segregating frameshift (c.591dupA [p.(Q198Tfs*21)]) and nonsense variant (c.2173A > T [p.(K725*)]) in KIAA0825 (also known as C5orf36). Although KIAA0825 encodes a protein of unknown function, it has been demonstrated that its murine ortholog is expressed during limb development. Our data contribute to the establishment of a catalog of genes important in limb patterning, which can aid in diagnosis and obtaining a better understanding of the biology of polydactyly.
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http://dx.doi.org/10.1007/s00439-019-02000-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6724712PMC
June 2019

PIGT-CDG, a disorder of the glycosylphosphatidylinositol anchor: description of 13 novel patients and expansion of the clinical characteristics.

Genet Med 2019 10 12;21(10):2216-2223. Epub 2019 Apr 12.

Danish Epilepsy Centre, Dianalund, Denmark.

Purpose: To provide a detailed electroclinical description and expand the phenotype of PIGT-CDG, to perform genotype-phenotype correlation, and to investigate the onset and severity of the epilepsy associated with the different genetic subtypes of this rare disorder. Furthermore, to use computer-assisted facial gestalt analysis in PIGT-CDG and to the compare findings with other glycosylphosphatidylinositol (GPI) anchor deficiencies.

Methods: We evaluated 13 children from eight unrelated families with homozygous or compound heterozygous pathogenic variants in PIGT.

Results: All patients had hypotonia, severe developmental delay, and epilepsy. Epilepsy onset ranged from first day of life to two years of age. Severity of the seizure disorder varied from treatable seizures to severe neonatal onset epileptic encephalopathies. The facial gestalt of patients resembled that of previously published PIGT patients as they were closest to the center of the PIGT cluster in the clinical face phenotype space and were distinguishable from other gene-specific phenotypes.

Conclusion: We expand our knowledge of PIGT. Our cases reaffirm that the use of genetic testing is essential for diagnosis in this group of disorders. Finally, we show that computer-assisted facial gestalt analysis accurately assigned PIGT cases to the multiple congenital anomalies-hypotonia-seizures syndrome phenotypic series advocating the additional use of next-generation phenotyping technology.
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http://dx.doi.org/10.1038/s41436-019-0512-3DOI Listing
October 2019

Correction: The ARID1B spectrum in 143 patients: from nonsyndromic intellectual disability to Coffin-Siris syndrome.

Genet Med 2019 Sep;21(9):2160-2161

University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands.

The original version of this Article contained an error in the spelling of the author Pleuntje J. van der Sluijs, which was incorrectly given as Eline (P. J.) van der Sluijs. This has now been corrected in both the PDF and HTML versions of the Article.
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http://dx.doi.org/10.1038/s41436-018-0368-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752317PMC
September 2019

Pathogenic variants in USP7 cause a neurodevelopmental disorder with speech delays, altered behavior, and neurologic anomalies.

Genet Med 2019 08 25;21(8):1797-1807. Epub 2019 Jan 25.

CHU Nantes, Service de Génétique Médicale, Nantes, France.

Purpose: Haploinsufficiency of USP7, located at chromosome 16p13.2, has recently been reported in seven individuals with neurodevelopmental phenotypes, including developmental delay/intellectual disability (DD/ID), autism spectrum disorder (ASD), seizures, and hypogonadism. Further, USP7 was identified to critically incorporate into the MAGEL2-USP7-TRIM27 (MUST), such that pathogenic variants in USP7 lead to altered endosomal F-actin polymerization and dysregulated protein recycling.

Methods: We report 16 newly identified individuals with heterozygous USP7 variants, identified by genome or exome sequencing or by chromosome microarray analysis. Clinical features were evaluated by review of medical records. Additional clinical information was obtained on the seven previously reported individuals to fully elucidate the phenotypic expression associated with USP7 haploinsufficiency.

Results: The clinical manifestations of these 23 individuals suggest a syndrome characterized by DD/ID, hypotonia, eye anomalies,feeding difficulties, GERD, behavioral anomalies, and ASD, and more specific phenotypes of speech delays including a nonverbal phenotype and abnormal brain magnetic resonance image findings including white matter changes based on neuroradiologic examination.

Conclusion: The consistency of clinical features among all individuals presented regardless of de novo USP7 variant type supports haploinsufficiency as a mechanism for pathogenesis and refines the clinical impact faced by affected individuals and caregivers.
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http://dx.doi.org/10.1038/s41436-019-0433-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752677PMC
August 2019

Familial Xp11.22 microdeletion including SHROOM4 and CLCN5 is associated with intellectual disability, short stature, microcephaly and Dent disease: a case report.

BMC Med Genomics 2019 01 10;12(1). Epub 2019 Jan 10.

Institute of Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

Background: Two interstitial microdeletions Xp11.22 including the CLCN5 and SHROOM4 genes were recently reported in a male individual affected with Dent disease, short stature, psychomotor delay and minor facial anomalies. Dent disease, characterized by a specific renal phenotype, is caused by truncating mutations of CLCN5 in the majority of affected cases.

Case Presentation: Here, we present clinical and molecular findings in a male patient with clinical signs of Dent disease, developmental delay, short stature, microcephaly, and facial dysmorphism. Using molecular karyotyping we identified a hemizygous interstitial microdeletion Xp11.23p.11.22 of about 700 kb, which was inherited from his asymptomatic mother. Among the six deleted genes is CLCN5, which explains the renal phenotype in our patient. SHROOM4, which is partially deleted in this patient, is involved in neuronal development and was shown to be associated with X-linked intellectual disability. This is a candidate gene, the loss of which is thought to be associated with his further clinical manifestations. To rule out mutations in other genes related to intellectual disability, whole exome sequencing was performed. No other pathogenic variants that could explain the phenotypic features, were found.

Conclusion: We compared the clinical findings of the patient presented here with the reported case with an Xp11.22 microdeletion including CLCN5 and SHROOM4 and re-defined the phenotypic spectrum associated with this microdeletion.
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http://dx.doi.org/10.1186/s12920-018-0471-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327553PMC
January 2019

Author Correction: Variants in exons 5 and 6 of ACTB cause syndromic thrombocytopenia.

Nat Commun 2018 11 19;9(1):4930. Epub 2018 Nov 19.

Institute for Clinical Genetics, TU Dresden, 01307, Dresden, Germany.

The original version of this Article contained an error in Figure 4. In panel i, the lower CYA and α-SMA images were inadvertently inverted. This has been corrected in both the PDF and HTML versions of the Article.
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http://dx.doi.org/10.1038/s41467-018-07404-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6242816PMC
November 2018

The ARID1B spectrum in 143 patients: from nonsyndromic intellectual disability to Coffin-Siris syndrome.

Genet Med 2019 06 8;21(6):1295-1307. Epub 2018 Nov 8.

University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands.

Purpose: Pathogenic variants in ARID1B are one of the most frequent causes of intellectual disability (ID) as determined by large-scale exome sequencing studies. Most studies published thus far describe clinically diagnosed Coffin-Siris patients (ARID1B-CSS) and it is unclear whether these data are representative for patients identified through sequencing of unbiased ID cohorts (ARID1B-ID). We therefore sought to determine genotypic and phenotypic differences between ARID1B-ID and ARID1B-CSS. In parallel, we investigated the effect of different methods of phenotype reporting.

Methods: Clinicians entered clinical data in an extensive web-based survey.

Results: 79 ARID1B-CSS and 64 ARID1B-ID patients were included. CSS-associated dysmorphic features, such as thick eyebrows, long eyelashes, thick alae nasi, long and/or broad philtrum, small nails and small or absent fifth distal phalanx and hypertrichosis, were observed significantly more often (p < 0.001) in ARID1B-CSS patients. No other significant differences were identified.

Conclusion: There are only minor differences between ARID1B-ID and ARID1B-CSS patients. ARID1B-related disorders seem to consist of a spectrum, and patients should be managed similarly. We demonstrated that data collection methods without an explicit option to report the absence of a feature (such as most Human Phenotype Ontology-based methods) tended to underestimate gene-related features.
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http://dx.doi.org/10.1038/s41436-018-0330-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752273PMC
June 2019

Variants in exons 5 and 6 of ACTB cause syndromic thrombocytopenia.

Nat Commun 2018 10 12;9(1):4250. Epub 2018 Oct 12.

Institute for Clinical Genetics, TU Dresden, Dresden, 01307, Germany.

Germline mutations in the ubiquitously expressed ACTB, which encodes β-cytoplasmic actin (CYA), are almost exclusively associated with Baraitser-Winter Cerebrofrontofacial syndrome (BWCFF). Here, we report six patients with previously undescribed heterozygous variants clustered in the 3'-coding region of ACTB. Patients present with clinical features distinct from BWCFF, including mild developmental disability, microcephaly, and thrombocytopenia with platelet anisotropy. Using patient-derived fibroblasts, we demonstrate cohort specific changes to β-CYA filament populations, which include the enhanced recruitment of thrombocytopenia-associated actin binding proteins (ABPs). These perturbed interactions are supported by in silico modeling and are validated in disease-relevant thrombocytes. Co-examination of actin and microtubule cytoskeleton constituents in patient-derived megakaryocytes and thrombocytes indicates that these β-CYA mutations inhibit the final stages of platelet maturation by compromising microtubule organization. Our results define an ACTB-associated clinical syndrome with a distinct genotype-phenotype correlation and delineate molecular mechanisms underlying thrombocytopenia in this patient cohort.
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http://dx.doi.org/10.1038/s41467-018-06713-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6185941PMC
October 2018

Genetic variants in components of the NALCN-UNC80-UNC79 ion channel complex cause a broad clinical phenotype (NALCN channelopathies).

Hum Genet 2018 Sep 23;137(9):753-768. Epub 2018 Aug 23.

Aix Marseille Univ, MMG, INSERM, Marseille, France.

NALCN is a conserved cation channel, which conducts a permanent sodium leak current and regulates resting membrane potential and neuronal excitability. It is part of a large ion channel complex, the "NALCN channelosome", consisting of multiple proteins including UNC80 and UNC79. The predominant neuronal expression pattern and its function suggest an important role in neuronal function and disease. So far, biallelic NALCN and UNC80 variants have been described in a small number of individuals leading to infantile hypotonia, psychomotor retardation, and characteristic facies 1 (IHPRF1, OMIM 615419) and 2 (IHPRF2, OMIM 616801), respectively. Heterozygous de novo NALCN missense variants in the S5/S6 pore-forming segments lead to congenital contractures of the limbs and face, hypotonia, and developmental delay (CLIFAHDD, OMIM 616266) with some clinical overlap. In this study, we present detailed clinical information of 16 novel individuals with biallelic NALCN variants, 1 individual with a heterozygous de novo NALCN missense variant and an interesting clinical phenotype without contractures, and 12 individuals with biallelic UNC80 variants. We report for the first time a missense NALCN variant located in the predicted S6 pore-forming unit inherited in an autosomal-recessive manner leading to mild IHPRF1. We show evidence of clinical variability, especially among IHPRF1-affected individuals, and discuss differences between the IHPRF1- and IHPRF2 phenotypes. In summary, we provide a comprehensive overview of IHPRF1 and IHPRF2 phenotypes based on the largest cohort of individuals reported so far and provide additional insights into the clinical phenotypes of these neurodevelopmental diseases to help improve counseling of affected families.
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http://dx.doi.org/10.1007/s00439-018-1929-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6671679PMC
September 2018

Autosomal dominant Robinow syndrome associated with a novel DVL3 splice mutation.

Am J Med Genet A 2018 04;176(4):992-996

Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, Berlin, Germany.

Robinow syndrome is a clinically and genetically heterogeneous disorder characterized by mesomelic limb shortening, distinctive facial features, and variable oral, cardiac, vertebral, and urogenital malformations. We identified the novel de novo splice acceptor mutation c.1715-2A > C in DVL3 in a 15-year-old female patient with typical features of Robinow syndrome. By studying DVL3 transcripts in this patient, we confirmed expression of both wild-type and mutant alleles. Mutant DVL3 mRNAs were found to harbor a deletion of four nucleotides at the beginning of exon 15 and encode a protein product with a distinct -1 reading-frame C-terminus. The data demonstrate that mutant DVL3 proteins associated with Robinow syndrome show truncation of the C-terminus and share 83 novel amino acid residues before the stop codon confirming highly specific DVL3 alterations to be associated with this syndrome. The phenotype of the Robinow syndrome-affected female reported here is typical as she shows mesomelia and mild hand anomalies as well as characteristic facial anomalies. She also exhibited a supraumbilical midline abdominal raphe which has not been observed in other patients with Robinow syndrome. In contrast to the clinical data of four previously reported individuals with DVL3-related Robinow syndrome, short stature was not present in this individual at the age of 15 years. These findings expand the clinical spectrum of Robinow syndrome associated with DVL3 mutations. To date, comparison of clinical data of DVL3 mutation-positive individuals with those of patients with genetically different forms did not allow delineation of gene-specific phenotypes.
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http://dx.doi.org/10.1002/ajmg.a.38635DOI Listing
April 2018

Characterization of glycosylphosphatidylinositol biosynthesis defects by clinical features, flow cytometry, and automated image analysis.

Genome Med 2018 01 9;10(1). Epub 2018 Jan 9.

The Jackson Laboratory for Genomic Medicine, 06032, Farmington, USA.

Background: Glycosylphosphatidylinositol biosynthesis defects (GPIBDs) cause a group of phenotypically overlapping recessive syndromes with intellectual disability, for which pathogenic mutations have been described in 16 genes of the corresponding molecular pathway. An elevated serum activity of alkaline phosphatase (AP), a GPI-linked enzyme, has been used to assign GPIBDs to the phenotypic series of hyperphosphatasia with mental retardation syndrome (HPMRS) and to distinguish them from another subset of GPIBDs, termed multiple congenital anomalies hypotonia seizures syndrome (MCAHS). However, the increasing number of individuals with a GPIBD shows that hyperphosphatasia is a variable feature that is not ideal for a clinical classification.

Methods: We studied the discriminatory power of multiple GPI-linked substrates that were assessed by flow cytometry in blood cells and fibroblasts of 39 and 14 individuals with a GPIBD, respectively. On the phenotypic level, we evaluated the frequency of occurrence of clinical symptoms and analyzed the performance of computer-assisted image analysis of the facial gestalt in 91 individuals.

Results: We found that certain malformations such as Morbus Hirschsprung and diaphragmatic defects are more likely to be associated with particular gene defects (PIGV, PGAP3, PIGN). However, especially at the severe end of the clinical spectrum of HPMRS, there is a high phenotypic overlap with MCAHS. Elevation of AP has also been documented in some of the individuals with MCAHS, namely those with PIGA mutations. Although the impairment of GPI-linked substrates is supposed to play the key role in the pathophysiology of GPIBDs, we could not observe gene-specific profiles for flow cytometric markers or a correlation between their cell surface levels and the severity of the phenotype. In contrast, it was facial recognition software that achieved the highest accuracy in predicting the disease-causing gene in a GPIBD.

Conclusions: Due to the overlapping clinical spectrum of both HPMRS and MCAHS in the majority of affected individuals, the elevation of AP and the reduced surface levels of GPI-linked markers in both groups, a common classification as GPIBDs is recommended. The effectiveness of computer-assisted gestalt analysis for the correct gene inference in a GPIBD and probably beyond is remarkable and illustrates how the information contained in human faces is pivotal in the delineation of genetic entities.
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http://dx.doi.org/10.1186/s13073-017-0510-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5759841PMC
January 2018
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