Publications by authors named "Naghmeh Dorrani"

27 Publications

  • Page 1 of 1

Expanding the genotypic and phenotypic spectrum in a diverse cohort of 104 individuals with Wiedemann-Steiner syndrome.

Am J Med Genet A 2021 Mar 30. Epub 2021 Mar 30.

Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.

Wiedemann-Steiner syndrome (WSS) is an autosomal dominant disorder caused by monoallelic variants in KMT2A and characterized by intellectual disability and hypertrichosis. We performed a retrospective, multicenter, observational study of 104 individuals with WSS from five continents to characterize the clinical and molecular spectrum of WSS in diverse populations, to identify physical features that may be more prevalent in White versus Black Indigenous People of Color individuals, to delineate genotype-phenotype correlations, to define developmental milestones, to describe the syndrome through adulthood, and to examine clinicians' differential diagnoses. Sixty-nine of the 82 variants (84%) observed in the study were not previously reported in the literature. Common clinical features identified in the cohort included: developmental delay or intellectual disability (97%), constipation (63.8%), failure to thrive (67.7%), feeding difficulties (66.3%), hypertrichosis cubiti (57%), short stature (57.8%), and vertebral anomalies (46.9%). The median ages at walking and first words were 20 months and 18 months, respectively. Hypotonia was associated with loss of function (LoF) variants, and seizures were associated with non-LoF variants. This study identifies genotype-phenotype correlations as well as race-facial feature associations in an ethnically diverse cohort, and accurately defines developmental trajectories, medical comorbidities, and long-term outcomes in individuals with WSS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.62124DOI Listing
March 2021

Novel NUDT2 variant causes intellectual disability and polyneuropathy.

Ann Clin Transl Neurol 2020 11 15;7(11):2320-2325. Epub 2020 Oct 15.

Department of Neurology, Olive View-UCLA Medical Center, Sylmar, California, USA.

Exome or genome sequencing was performed to identify the genetic etiology for the clinical presentation of global developmental delay, intellectual disability, and sensorimotor neuropathy with associated distal weakness in two unrelated families. A homozygous frameshift variant c.186delA (p.A63Qfs*3) in the NUDT2 gene was identified in cases 1 and 2 from one family and a third case from another family. Variants in NUDT2 were previously shown to cause intellectual disability, but here we expand the phenotype by demonstrating its association with distal upper and lower extremity weakness due to a sensorimotor polyneuropathy with demyelinating and/or axonal features.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/acn3.51209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7664258PMC
November 2020

De Novo SOX6 Variants Cause a Neurodevelopmental Syndrome Associated with ADHD, Craniosynostosis, and Osteochondromas.

Am J Hum Genet 2020 06 21;106(6):830-845. Epub 2020 May 21.

Roberts Individualized Medical Genetics Center, Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.

SOX6 belongs to a family of 20 SRY-related HMG-box-containing (SOX) genes that encode transcription factors controlling cell fate and differentiation in many developmental and adult processes. For SOX6, these processes include, but are not limited to, neurogenesis and skeletogenesis. Variants in half of the SOX genes have been shown to cause severe developmental and adult syndromes, referred to as SOXopathies. We here provide evidence that SOX6 variants also cause a SOXopathy. Using clinical and genetic data, we identify 19 individuals harboring various types of SOX6 alterations and exhibiting developmental delay and/or intellectual disability; the individuals are from 17 unrelated families. Additional, inconstant features include attention-deficit/hyperactivity disorder (ADHD), autism, mild facial dysmorphism, craniosynostosis, and multiple osteochondromas. All variants are heterozygous. Fourteen are de novo, one is inherited from a mosaic father, and four offspring from two families have a paternally inherited variant. Intragenic microdeletions, balanced structural rearrangements, frameshifts, and nonsense variants are predicted to inactivate the SOX6 variant allele. Four missense variants occur in residues and protein regions highly conserved evolutionarily. These variants are not detected in the gnomAD control cohort, and the amino acid substitutions are predicted to be damaging. Two of these variants are located in the HMG domain and abolish SOX6 transcriptional activity in vitro. No clear genotype-phenotype correlations are found. Taken together, these findings concur that SOX6 haploinsufficiency leads to a neurodevelopmental SOXopathy that often includes ADHD and abnormal skeletal and other features.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2020.04.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7273536PMC
June 2020

Genetic characterization and long-term management of severely affected siblings with intellectual developmental disorder with cardiac arrhythmia syndrome.

Mol Genet Metab Rep 2020 Jun 6;23:100582. Epub 2020 Apr 6.

Departments of Pediatrics and Mattel Children's Hospital at UCLA, Los Angeles, CA, United States of America.

We report two brothers with severe global cognitive and motor delay, cortical visual impairment and sick sinus syndrome who were born to consanguineous parents. Standard genetic evaluations did not reveal the cause of their mental retardation. As expected, chromosomal microarray (CMA) revealed extensive regions of homozygosity. Exome sequencing revealed that both affected boys were homozygous for a nonsense mutation in the G-protein β5 () gene (NM_016194.3:c.1032C > G; Tyr344Ter), and that the parents were carriers of this mutation. No other DNA variants that were explanatory for the sick sinus or the developmental delay/intellectual disability were identified, and no other clinical parameters are likely to have contributed to this unusual combination of phenotypes. The neurologic features of our patients are more severe than those of most of the other patients previously reported with variants, probably because of the homozygous, complete loss-of-function (nonsense/stop-gain) nature of their variant, and their clinical course has been monitored for longer duration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ymgmr.2020.100582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7138921PMC
June 2020

A case report of a novel germline GNAS mutation in sonic hedgehog activated medulloblastoma.

Pediatr Blood Cancer 2020 03 2;67(3):e28103. Epub 2019 Dec 2.

Division of Hematology, Oncology and Blood and Marrow Transplantation, Children's Hospital of, Los Angeles, Los Angeles, California.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/pbc.28103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307637PMC
March 2020

Confidential genetic testing and electronic health records: A survey of current practices among Huntington disease testing centers.

Mol Genet Genomic Med 2020 01 7;8(1):e1026. Epub 2019 Nov 7.

University of California, Los Angeles Los Angeles, CA, USA.

Background: Clinical care teams providing presymptomatic genetic testing often employ advanced confidentiality practices for documentation and result storage. However, patient requests for increased confidentiality may be in conflict with the legal obligations of medical providers to document patient care activities in the electronic health record (EHR). Huntington disease presents a representative case study for investigating the ways centers currently balance the requirements of EHRs with the privacy demands of patients seeking presymptomatic genetic testing.

Methods: We surveyed 23 HD centers (53% response rate) regarding their use of the EHR for presymptomatic HD testing.

Results: Our survey revealed that clinical care teams and laboratories have each developed their own practices, which are cumbersome and often include EHR avoidance. We found that a majority of HD care teams record appointments in the EHR (91%), often using vague notes. Approximately half of the care teams (52%) keep presymptomatic results of out of the EHR.

Conclusion: As genetic knowledge grows, linking more genes to late-onset conditions, institutions will benefit from having professional recommendations to guide development of policies for EHR documentation of presymptomatic genetic results. Policies must be sensitive to the ethical differences and patient demands for presymptomatic genetic testing compared to those undergoing confirmatory genetic testing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mgg3.1026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6978271PMC
January 2020

Diagnostic utility of transcriptome sequencing for rare Mendelian diseases.

Genet Med 2020 03 14;22(3):490-499. Epub 2019 Oct 14.

Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA.

Purpose: We investigated the value of transcriptome sequencing (RNAseq) in ascertaining the consequence of DNA variants on RNA transcripts to improve the diagnostic rate from exome or genome sequencing for undiagnosed Mendelian diseases spanning a wide spectrum of clinical indications.

Methods: From 234 subjects referred to the Undiagnosed Diseases Network, University of California-Los Angeles clinical site between July 2014 and August 2018, 113 were enrolled for high likelihood of having rare undiagnosed, suspected genetic conditions despite thorough prior clinical evaluation. Exome or genome sequencing and RNAseq were performed, and RNAseq data was integrated with genome sequencing data for DNA variant interpretation genome-wide.

Results: The molecular diagnostic rate by exome or genome sequencing was 31%. Integration of RNAseq with genome sequencing resulted in an additional seven cases with clear diagnosis of a known genetic disease. Thus, the overall molecular diagnostic rate was 38%, and 18% of all genetic diagnoses returned required RNAseq to determine variant causality.

Conclusion: In this rare disease cohort with a wide spectrum of undiagnosed, suspected genetic conditions, RNAseq analysis increased the molecular diagnostic rate above that possible with genome sequencing analysis alone even without availability of the most appropriate tissue type to assess.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-019-0672-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7405636PMC
March 2020

New insights into DNA methylation signatures: SMARCA2 variants in Nicolaides-Baraitser syndrome.

BMC Med Genomics 2019 07 9;12(1):105. Epub 2019 Jul 9.

Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.

Background: Nicolaides-Baraitser syndrome (NCBRS) is a neurodevelopmental disorder caused by pathogenic sequence variants in SMARCA2 which encodes the catalytic component of the chromatin remodeling BAF complex. Pathogenic variants in genes that encode epigenetic regulators have been associated with genome-wide changes in DNA methylation (DNAm) in affected individuals termed DNAm signatures.

Methods: Genome-wide DNAm was assessed in whole-blood samples from the individuals with pathogenic SMARCA2 variants and NCBRS diagnosis (n = 8) compared to neurotypical controls (n = 23) using the Illumina MethylationEPIC array. Differential methylated CpGs between groups (DNAm signature) were identified and used to generate a model enabling classification variants of uncertain significance (VUS; n = 9) in SMARCA2 as "pathogenic" or "benign". A validation cohort of NCBRS cases (n = 8) and controls (n = 96) demonstrated 100% model sensitivity and specificity.

Results: We identified a DNAm signature of 429 differentially methylated CpG sites in individuals with NCBRS. The genes to which these CpG sites map are involved in cell differentiation, calcium signaling, and neuronal function consistent with NCBRS pathophysiology. DNAm model classifications of VUS were concordant with the clinical phenotype; those within the SMARCA2 ATPase/helicase domain classified as "pathogenic". A patient with a mild neurodevelopmental NCBRS phenotype and a VUS distal to the ATPase/helicase domain did not score as pathogenic, clustering away from cases and controls. She demonstrated an intermediate DNAm profile consisting of one subset of signature CpGs with methylation levels characteristic of controls and another characteristic of NCBRS cases; each mapped to genes with ontologies consistent with the patient's unique clinical presentation.

Conclusions: Here we find that a DNAm signature of SMARCA2 pathogenic variants in NCBRS maps to CpGs relevant to disorder pathophysiology, classifies VUS, and is sensitive to the position of the variant in SMARCA2. The patient with an intermediate model score demonstrating a unique genotype-epigenotype-phenotype correlation underscores the potential utility of this signature as a functionally relevant VUS classification system scalable beyond binary "benign" versus "pathogenic" scoring. This is a novel feature of DNAm signatures that could enable phenotypic predictions from genotype data. Our findings also demonstrate that DNAm signatures can be domain-specific, highlighting the precision with which they can reflect genotypic variation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12920-019-0555-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6617651PMC
July 2019

SLC35A2-CDG: Functional characterization, expanded molecular, clinical, and biochemical phenotypes of 30 unreported Individuals.

Hum Mutat 2019 07 24;40(7):908-925. Epub 2019 Apr 24.

Department of Metabolic Medicine, The Royal Children's Hospital, Melbourne, Parkville, Victoria, Australia.

Pathogenic de novo variants in the X-linked gene SLC35A2 encoding the major Golgi-localized UDP-galactose transporter required for proper protein and lipid glycosylation cause a rare type of congenital disorder of glycosylation known as SLC35A2-congenital disorders of glycosylation (CDG; formerly CDG-IIm). To date, 29 unique de novo variants from 32 unrelated individuals have been described in the literature. The majority of affected individuals are primarily characterized by varying degrees of neurological impairments with or without skeletal abnormalities. Surprisingly, most affected individuals do not show abnormalities in serum transferrin N-glycosylation, a common biomarker for most types of CDG. Here we present data characterizing 30 individuals and add 26 new variants, the single largest study involving SLC35A2-CDG. The great majority of these individuals had normal transferrin glycosylation. In addition, expanding the molecular and clinical spectrum of this rare disorder, we developed a robust and reliable biochemical assay to assess SLC35A2-dependent UDP-galactose transport activity in primary fibroblasts. Finally, we show that transport activity is directly correlated to the ratio of wild-type to mutant alleles in fibroblasts from affected individuals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/humu.23731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6661012PMC
July 2019

Understanding Adult Participant and Parent Empowerment Prior to Evaluation in the Undiagnosed Diseases Network.

J Genet Couns 2018 09 1;27(5):1087-1101. Epub 2018 Mar 1.

Division of Medical Genetics and Genomic Medicine, Vanderbilt University, Nashville, TN, USA.

The burden of living with an undiagnosed condition is high and includes physical and emotional suffering, frustrations, and uncertainty. For patients and families experiencing these stressors, higher levels of empowerment may be associated with better outcomes. Thus, it is important to understand the experiences of patients with undiagnosed conditions and their families affected by undiagnosed conditions in order to identify strategies for fostering empowerment. In this study, we used the Genetic Counseling Outcome Scale (GCOS-24) to assess levels of empowerment and support group participation in 35 adult participants and 67 parents of child participants in the Undiagnosed Diseases Network (UDN) prior to their UDN in-person evaluation. Our results revealed significantly lower empowerment scores on the GCOS-24 in adult participants compared to parents of child participants [t(100) = - 3.01, p = 0.003, average difference = - 11.12, 95% CI (- 3.78, - 18.46)] and no significant association between support group participation and empowerment scores. The majority of participants (84.3%, 86/102) are not currently participating in any support groups, and participation rates were not significantly different for adult participants and parents of child participants (11.4 vs. 19.7%, respectively, FE p = 0.40). Open-ended responses provided additional insight into support group participation, the challenges of living with undiagnosed conditions, and positive coping strategies. Future research will evaluate the extent to which empowerment scores change as participation in the UDN unfolds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10897-018-0228-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132569PMC
September 2018

Coupling clinical exome sequencing with functional characterization studies to diagnose a patient with familial Mediterranean fever and haploinsufficiency syndromes.

Clin Case Rep 2017 06 18;5(6):833-840. Epub 2017 Apr 18.

UCLA Department of Pathology and Laboratory Medicine David Geffen School of Medicine University of California, Los Angeles Los Angeles California.

Clinicians should consider that clinical exome sequencing provides the unique potential to disentangle complex phenotypes into multiple genetic etiologies. Further, functional studies on variants of uncertain significance are necessary to arrive at an accurate diagnosis for the patient.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ccr3.904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5458005PMC
June 2017

Defining the diverse spectrum of inversions, complex structural variation, and chromothripsis in the morbid human genome.

Genome Biol 2017 03 6;18(1):36. Epub 2017 Mar 6.

Molecular Neurogenetics Unit and Psychiatric and Neurodevelopmental Genetics Unit, Center for Genomic Medicine, and Department of Neurology, Massachusetts General Hospital, Boston, MA, 02114, USA.

Background: Structural variation (SV) influences genome organization and contributes to human disease. However, the complete mutational spectrum of SV has not been routinely captured in disease association studies.

Results: We sequenced 689 participants with autism spectrum disorder (ASD) and other developmental abnormalities to construct a genome-wide map of large SV. Using long-insert jumping libraries at 105X mean physical coverage and linked-read whole-genome sequencing from 10X Genomics, we document seven major SV classes at ~5 kb SV resolution. Our results encompass 11,735 distinct large SV sites, 38.1% of which are novel and 16.8% of which are balanced or complex. We characterize 16 recurrent subclasses of complex SV (cxSV), revealing that: (1) cxSV are larger and rarer than canonical SV; (2) each genome harbors 14 large cxSV on average; (3) 84.4% of large cxSVs involve inversion; and (4) most large cxSV (93.8%) have not been delineated in previous studies. Rare SVs are more likely to disrupt coding and regulatory non-coding loci, particularly when truncating constrained and disease-associated genes. We also identify multiple cases of catastrophic chromosomal rearrangements known as chromoanagenesis, including somatic chromoanasynthesis, and extreme balanced germline chromothripsis events involving up to 65 breakpoints and 60.6 Mb across four chromosomes, further defining rare categories of extreme cxSV.

Conclusions: These data provide a foundational map of large SV in the morbid human genome and demonstrate a previously underappreciated abundance and diversity of cxSV that should be considered in genomic studies of human disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13059-017-1158-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5338099PMC
March 2017

A Recurrent De Novo Variant in NACC1 Causes a Syndrome Characterized by Infantile Epilepsy, Cataracts, and Profound Developmental Delay.

Am J Hum Genet 2017 Feb 26;100(2):343-351. Epub 2017 Jan 26.

Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.

Whole-exome sequencing (WES) has increasingly enabled new pathogenic gene variant identification for undiagnosed neurodevelopmental disorders and provided insights into both gene function and disease biology. Here, we describe seven children with a neurodevelopmental disorder characterized by microcephaly, profound developmental delays and/or intellectual disability, cataracts, severe epilepsy including infantile spasms, irritability, failure to thrive, and stereotypic hand movements. Brain imaging in these individuals reveals delay in myelination and cerebral atrophy. We observe an identical recurrent de novo heterozygous c.892C>T (p.Arg298Trp) variant in the nucleus accumbens associated 1 (NACC1) gene in seven affected individuals. One of the seven individuals is mosaic for this variant. NACC1 encodes a transcriptional repressor implicated in gene expression and has not previously been associated with germline disorders. The probability of finding the same missense NACC1 variant by chance in 7 out of 17,228 individuals who underwent WES for diagnoses of neurodevelopmental phenotypes is extremely small and achieves genome-wide significance (p = 1.25 × 10). Selective constraint against missense variants in NACC1 makes this excess of an identical missense variant in all seven individuals more remarkable. Our findings are consistent with a germline recurrent mutational hotspot associated with an allele-specific neurodevelopmental phenotype in NACC1.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2016.12.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5294886PMC
February 2017

Effects of a Mutation in the Gene Encoding the Mitochondrial Co-chaperonin HSP10 and Its Potential Association with a Neurological and Developmental Disorder.

Front Mol Biosci 2016 7;3:65. Epub 2016 Oct 7.

Research Unit for Molecular Medicine, Aarhus University and Aarhus University Hospital Aarhus, Denmark.

We here report molecular investigations of a missense mutation in the gene encoding the HSP10 subunit of the HSP60/ HSP10 chaperonin complex that assists protein folding in the mitochondrial matrix. The mutation was identified in an infant who came to clinical attention due to infantile spasms at 3 months of age. Clinical exome sequencing revealed heterozygosity for a NM_002157.2:c.217C>T mutation causing replacement of leucine with phenylalanine at position 73 of the HSP10 protein. This variation has never been observed in public exome sequencing databases or the literature. To evaluate whether the mutation may be disease-associated we investigated its effects by and studies. Our studies indicated that the purified mutant protein was functional, yet its thermal stability, spontaneous refolding propensity, and resistance to proteolytic treatment were profoundly impaired. Mass spectrometric analysis of patient fibroblasts revealed barely detectable levels of HSP10-p.Leu73Phe protein resulting in an almost 2-fold decrease of the ratio of HSP10 to HSP60 subunits. Amounts of the mitochondrial superoxide dismutase SOD2, a protein whose folding is known to strongly depend on the HSP60/HSP10 complex, were decreased to approximately 20% in patient fibroblasts in spite of unchanged SOD2 transcript levels. As a likely consequence, mitochondrial superoxide levels were increased about 2-fold. Although, we cannot exclude other causative or contributing factors, our experimental data support the notion that the HSP10-p.Leu73Phe mutation could be the cause or a strong contributing factor for the disorder in the described patient.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmolb.2016.00065DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5053987PMC
October 2016

An infant with MLH3 variants, FOXG1-duplication and multiple, benign cranial and spinal tumors: A clinical exome sequencing study.

Genes Chromosomes Cancer 2016 Feb 6;55(2):131-42. Epub 2015 Nov 6.

Pathology and Laboratory Medicine, University of California at Los Angeles, David Geffen School of Medicine, Los Angeles, CA, 90095.

A 4-month-old male infant presented with severe developmental delay, cerebellar, brainstem, and cutaneous hemangiomas, bilateral tumors (vestibular, hypoglossal, cervical, and lumbar spinal), and few café-au-lait macules. Cerebellar and lumbar tumor biopsies revealed venous telangiectasia and intraneural perineuroma, respectively. Sequencing NF1, NF2, and RASA1 (blood), and NF2 and SMARCB1 (lumbar biopsy) was negative for pathogenic mutations. Clinical exome sequencing (CES), requested for tumor syndrome diagnosis, revealed two heterozygous missense variants, c.359T>C;p.Phe120Ser and c.3344G>A;p.Arg1115Gln, in MLH3 (NM_001040108.1), a DNA mismatch repair (MMR) gene, Polyphen-predicted as probably damaging, and benign, respectively. Sanger sequencing confirmed both variants in the proband, and their absence in the mother; biological father unavailable. Both biopsied tissues were negative for microsatellite instability, and expressed MLH1, MSH2, PMS2, MSH6, and MLH3 immunohistochemically. Chromosomal microarray showed a 133 kb segment copy number duplication of 14q12 region encompassing FOXG1, possibly explaining the developmental delay, but not the tumors. The presence of MLH3 variants with multiple benign neural and vascular tumors was intriguing for their possible role in the pathogenesis of these neoplasms, which were suspicious for, but not diagnostic of, constitutional MMR deficiency. However, functional assays of non-neoplastic patient-derived cells showed intact base-base MMR function. Also, no previous FOXG1-aberrant patient was reported with tumors. We now report a 3-year-old FOXG1-duplicated patient with a yet undescribed tumor syndrome with clinical features of neurofibromatosis types I and II, where several validation studies could not ascertain the significance of CES findings; further studies may elucidate precise mechanisms and diagnosis for clinical management, including tumor surveillance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/gcc.22319DOI Listing
February 2016

DYRK1A haploinsufficiency causes a new recognizable syndrome with microcephaly, intellectual disability, speech impairment, and distinct facies.

Eur J Hum Genet 2015 Nov 6;23(11):1473-81. Epub 2015 May 6.

Department of Medical Genetics, Cumming School of Medicine, University of Calgary, and Alberta Children's Hospital Research Institute for Child and Maternal Health, Calgary, AB, Canada.

Dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1 A (DYRK1A ) is a highly conserved gene located in the Down syndrome critical region. It has an important role in early development and regulation of neuronal proliferation. Microdeletions of chromosome 21q22.12q22.3 that include DYRK1A (21q22.13) are rare and only a few pathogenic single-nucleotide variants (SNVs) in the DYRK1A gene have been described, so as of yet, the landscape of DYRK1A disruptions and their associated phenotype has not been fully explored. We have identified 14 individuals with de novo heterozygous variants of DYRK1A; five with microdeletions, three with small insertions or deletions (INDELs) and six with deleterious SNVs. The analysis of our cohort and comparison with published cases reveals that phenotypes are consistent among individuals with the 21q22.12q22.3 microdeletion and those with translocation, SNVs, or INDELs within DYRK1A. All individuals shared congenital microcephaly at birth, intellectual disability, developmental delay, severe speech impairment, short stature, and distinct facial features. The severity of the microcephaly varied from -2 SD to -5 SD. Seizures, structural brain abnormalities, eye defects, ataxia/broad-based gait, intrauterine growth restriction, minor skeletal abnormalities, and feeding difficulties were present in two-thirds of all affected individuals. Our study demonstrates that haploinsufficiency of DYRK1A results in a new recognizable syndrome, which should be considered in individuals with Angelman syndrome-like features and distinct facial features. Our report represents the largest cohort of individuals with DYRK1A disruptions to date, and is the first attempt to define consistent genotype-phenotype correlations among subjects with 21q22.13 microdeletions and DYRK1A SNVs or small INDELs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ejhg.2015.71DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4613469PMC
November 2015

De novo nonsense mutations in KAT6A, a lysine acetyl-transferase gene, cause a syndrome including microcephaly and global developmental delay.

Am J Hum Genet 2015 Mar 26;96(3):498-506. Epub 2015 Feb 26.

Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA. Electronic address:

Chromatin remodeling through histone acetyltransferase (HAT) and histone deactylase (HDAC) enzymes affects fundamental cellular processes including the cell-cycle, cell differentiation, metabolism, and apoptosis. Nonsense mutations in genes that are involved in histone acetylation and deacetylation result in multiple congenital anomalies with most individuals displaying significant developmental delay, microcephaly and dysmorphism. Here, we report a syndrome caused by de novo heterozygous nonsense mutations in KAT6A (a.k.a., MOZ, MYST3) identified by clinical exome sequencing (CES) in four independent families. The same de novo nonsense mutation (c.3385C>T [p.Arg1129∗]) was observed in three individuals, and the fourth individual had a nearby de novo nonsense mutation (c.3070C>T [p.Arg1024∗]). Neither of these variants was present in 1,815 in-house exomes or in public databases. Common features among all four probands include primary microcephaly, global developmental delay including profound speech delay, and craniofacial dysmorphism, as well as more varied features such as feeding difficulties, cardiac defects, and ocular anomalies. We further demonstrate that KAT6A mutations result in dysregulation of H3K9 and H3K18 acetylation and altered P53 signaling. Through histone and non-histone acetylation, KAT6A affects multiple cellular processes and illustrates the complex role of acetylation in regulating development and disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajhg.2015.01.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375619PMC
March 2015

Clinical exome sequencing for genetic identification of rare Mendelian disorders.

JAMA 2014 Nov;312(18):1880-7

Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles2Clinical Genomics Center, David Geffen School of Medicine, University of California, Los Angeles6Department of Human Genetics, David Ge.

Importance: Clinical exome sequencing (CES) is rapidly becoming a common molecular diagnostic test for individuals with rare genetic disorders.

Objective: To report on initial clinical indications for CES referrals and molecular diagnostic rates for different indications and for different test types.

Design, Setting, And Participants: Clinical exome sequencing was performed on 814 consecutive patients with undiagnosed, suspected genetic conditions at the University of California, Los Angeles, Clinical Genomics Center between January 2012 and August 2014. Clinical exome sequencing was conducted as trio-CES (both parents and their affected child sequenced simultaneously) to effectively detect de novo and compound heterozygous variants or as proband-CES (only the affected individual sequenced) when parental samples were not available.

Main Outcomes And Measures: Clinical indications for CES requests, molecular diagnostic rates of CES overall and for phenotypic subgroups, and differences in molecular diagnostic rates between trio-CES and proband-CES.

Results: Of the 814 cases, the overall molecular diagnosis rate was 26% (213 of 814; 95% CI, 23%-29%). The molecular diagnosis rate for trio-CES was 31% (127 of 410 cases; 95% CI, 27%-36%) and 22% (74 of 338 cases; 95% CI, 18%-27%) for proband-CES. In cases of developmental delay in children (<5 years, n = 138), the molecular diagnosis rate was 41% (45 of 109; 95% CI, 32%-51%) for trio-CES cases and 9% (2 of 23, 95% CI, 1%-28%) for proband-CES cases. The significantly higher diagnostic yield (P value = .002; odds ratio, 7.4 [95% CI, 1.6-33.1]) of trio-CES was due to the identification of de novo and compound heterozygous variants.

Conclusions And Relevance: In this sample of patients with undiagnosed, suspected genetic conditions, trio-CES was associated with higher molecular diagnostic yield than proband-CES or traditional molecular diagnostic methods. Additional studies designed to validate these findings and to explore the effect of this approach on clinical and economic outcomes are warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1001/jama.2014.14604DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4278636PMC
November 2014

De Novo variants in the KMT2A (MLL) gene causing atypical Wiedemann-Steiner syndrome in two unrelated individuals identified by clinical exome sequencing.

BMC Med Genet 2014 May 1;15:49. Epub 2014 May 1.

Clinical Genomics Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.

Background: Wiedemann-Steiner Syndrome (WSS) is characterized by short stature, a variety of dysmorphic facial and skeletal features, characteristic hypertrichosis cubiti (excessive hair on the elbows), mild-to-moderate developmental delay and intellectual disability. [MIM#: 605130]. Here we report two unrelated children for whom clinical exome sequencing of parent-proband trios was performed at UCLA, resulting in a molecular diagnosis of WSS and atypical clinical presentation.

Case Presentation: For patient 1, clinical features at 9 years of age included developmental delay, craniofacial abnormalities, and multiple minor anomalies. Patient 2 presented at 1 year of age with developmental delay, microphthalmia, partial 3-4 left hand syndactyly, and craniofacial abnormalities. A de novo missense c.4342T>C variant and a de novo splice site c.4086+G>A variant were identified in the KMT2A gene in patients 1 and 2, respectively.

Conclusions: Based on the clinical and molecular findings, both patients appear to have novel presentations of WSS. As the hallmark hypertrichosis cubiti was not initially appreciated in either case, this syndrome was not suspected during the clinical evaluation. This report expands the phenotypic spectrum of the clinical phenotypes and KMT2A variants associated with WSS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2350-15-49DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072606PMC
May 2014

First report of a de novo 18q11.2 microdeletion including GATA6 associated with complex congenital heart disease and renal abnormalities.

Am J Med Genet A 2013 Jul 21;161A(7):1773-8. Epub 2013 May 21.

Department of Pathology, Laboratory Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.

Deletions of the long arm of chromosome 18 have been previously reported in many patients. Most cases involve the more distal regions of the long arm (18q21.1->qter). However, proximal interstitial deletions involving 18q11.2 are extremely rare. Here we report on a 14-month-old female with a 4.7 Mb (19,667,062-24,401,876 hg19) de novo interstitial deletion within chromosomal band 18q11.2, which includes GATA6 and 24 other RefSeq genes. The clinical features of our patient include complex congenital heart defects, a double outlet right ventricle, a subaortic ventricular septal defect, D-malposed great arteries, an atrial septal defect, a dysplastic aortic valve and patent ductus arteriosus. In addition, she had renal anomalies-a duplicated collecting system on the left and mild right hydronephrosis. These heart and renal defects are not reported in other patients with 18q proximal interstitial deletions. Heterozygous point mutations in GATA6, encoding for a zinc finger transcription factor, have been shown to cause congenital heart defects. Given the well-established biological role of GATA6 in cardiac development, a deletion of GATA6 is very likely responsible for our patient's complex congenital heart defects. This is the smallest and most proximal 18q11.2 deletion involving GATA6 that is associated with complex congenital heart disease and renal anomalies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.35974DOI Listing
July 2013

Biochemical, molecular, and clinical characteristics of children with short chain acyl-CoA dehydrogenase deficiency detected by newborn screening in California.

Mol Genet Metab 2012 May 9;106(1):55-61. Epub 2012 Feb 9.

Department of Pediatrics, University of California at Los Angeles, Los Angeles, CA, USA.

Background: Short-chain acyl-CoA dehydrogenase deficiency (SCADD) is an autosomal recessive inborn error of mitochondrial fatty acid oxidation with highly variable biochemical, genetic, and clinical characteristics. SCADD has been associated with accumulation of butyryl-CoA byproducts, including butyrylcarnitine (C4), butyrylglycine, ethylmalonic acid (EMA), and methylsuccinic acid (MS) in body fluid and tissues. Differences in genotype frequencies have been shown between patients diagnosed clinically versus those diagnosed by newborn screening. Moreover, while patients diagnosed clinically have a variable clinical presentation including developmental delay, ketotic hypoglycemia, epilepsy and behavioral disorders, studies suggest patients diagnosed by newborn screening are largely asymptomatic. Scant information is published about the biochemical, genetic and clinical outcome of SCADD patients diagnosed by newborn screening.

Methods: We collected California newborn screening, follow-up biochemical levels, and ACADS mutation data from September, 2005 through April, 2010. We retrospectively reviewed available data on SCADD cases diagnosed by newborn screening for clinical outcomes.

Results: During the study period, 2,632,058 newborns were screened and 76 confirmed SCADD cases were identified. No correlations between initial C4 value and follow-up biochemical markers (C4, EMA or MS levels) were found in the 76 cases studied. We found significant correlation between urine EMA versus MS, and correlation between follow-up C4 versus urine EMA. Of 22 cases where ACADS gene sequencing was performed: 7 had two or more deleterious mutations; 8 were compound heterozygotes for a deleterious mutation and common variant; 7 were homozygous for the common variant c.625G>A; and 1 was heterozygous for c.625G>A. Significant increases in mean urine EMA and MS levels were noted in patients with two or more deleterious mutations versus mutation heterozygotes or common polymorphism homozygotes. Clinical outcome data was available in 31 patients with follow-up extending from 0.5 to 60 months. None developed epilepsy or behavioral disorders, and three patients had isolated speech delay. Hypoglycemia occurred in two patients, both in the neonatal period. The first patient had concomitant meconium aspiration; the other presented with central apnea, poor feeding, and hypotonia. The latter, a c.625G>A homozygote, has had persistent elevations in both short- and medium-chain acylcarnitines; diagnostic workup in this case is extensive and ongoing.

Conclusions: This study examines the largest series to date of SCADD patients identified by newborn screening. Our results suggest that confirmatory tests may be useful to differentiate patients with common variants from those with deleterious mutations. This study also provides evidence to suggest that, even when associated with deleterious mutations, SCADD diagnosed by newborn screening presents largely as a benign condition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ymgme.2012.02.007DOI Listing
May 2012

Autistic disorder associated with a paternally derived unbalanced translocation leading to duplication of chromosome 15pter-q13.2: a case report.

Mol Cytogenet 2009 Dec 18;2:27. Epub 2009 Dec 18.

Department of Biological Sciences, University of Delaware, Newark, USA.

Autism spectrum disorders have been associated with maternally derived duplications that involve the imprinted region on the proximal long arm of chromosome 15. Here we describe a boy with a chromosome 15 duplication arising from a 3:1 segregation error of a paternally derived translocation between chromosome 15q13.2 and chromosome 9q34.12, which led to trisomy of chromosome 15pter-q13.2 and 9q34.12-qter. Using array comparative genome hybridization, we localized the breakpoints on both chromosomes and sequence homology suggests that the translocation arose from non-allelic homologous recombination involving the low copy repeats on chromosome 15. The child manifests many characteristics of the maternally-derived duplication chromosome 15 phenotype including developmental delays with cognitive impairment, autism, hypotonia and facial dysmorphisms with nominal overlap of the most general symptoms found in duplications of chromosome 9q34. This case suggests that biallelically expressed genes on proximal 15q contribute to the idic(15) autism phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1755-8166-2-27DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2803171PMC
December 2009

Multiple forms of atypical rearrangements generating supernumerary derivative chromosome 15.

BMC Genet 2008 Jan 4;9. Epub 2008 Jan 4.

Nemours Biomedical Research, Alfred I, duPont Hospital for Children, Wilmington, Delaware, 19803, USA.

Background: Maternally-derived duplications that include the imprinted region on the proximal long arm of chromosome 15 underlie a complex neurobehavioral disorder characterized by cognitive impairment, seizures and a substantial risk for autism spectrum disorders1. The duplications most often take the form of a supernumerary pseudodicentric derivative chromosome 15 [der(15)] that has been called inverted duplication 15 or isodicentric 15 [idic(15)], although interstitial rearrangements also occur. Similar to the deletions found in most cases of Angelman and Prader Willi syndrome, the duplications appear to be mediated by unequal homologous recombination involving low copy repeats (LCR) that are found clustered in the region. Five recurrent breakpoints have been described in most cases of segmental aneuploidy of chromosome 15q11-q13 and previous studies have shown that most idic(15) chromosomes arise through BP3:BP3 or BP4:BP5 recombination events.

Results: Here we describe four duplication chromosomes that show evidence of atypical recombination events that involve regions outside the common breakpoints. Additionally, in one patient with a mosaic complex der(15), we examined homologous pairing of chromosome 15q11-q13 alleles by FISH in a region of frontal cortex, which identified mosaicism in this tissue and also demonstrated pairing of the signals from the der(15) and the normal homologues.

Conclusion: Involvement of atypical BP in the generation of idic(15) chromosomes can lead to considerable structural heterogeneity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1471-2156-9-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2249594PMC
January 2008

Phenotypic manifestations of MECP2 mutations in classical and atypical Rett syndrome.

Am J Med Genet A 2004 Apr;126A(2):129-40

Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Room H3B-337, PO Box 269, Wilmington, DE 19899, USA.

Since the identification of mutations in MECP2 in girls and women with apparent Rett syndrome, numerous efforts have been made to develop phenotype-genotype correlations. These studies have produced conflicting results in part related to use of different clinical severity scales, different diagnostic criteria, and different stratification by age and mutation group as well as the possible effects of unbalanced X-chromosome inactivation. The present study applied a revised ordinal scoring system that allowed for correction for patient ages. We analyzed 85 patients with mutation in MECP2. Sixty-five (76%) had one of eight common mutations. Patients with missense mutations had lower total severity scores and better language performance than those with nonsense mutations. No difference was noted between severity scores for mutations in the methyl-binding domain (MBD) and the transcriptional repression domain (TRD). However, patients with missense mutations in TRD had the best overall scores and better preservation of head growth and language skills. Analysis of specific mutation groups demonstrated a striking difference for patients with the R306C mutation including better overall score, later regression, and better language with less motoric impairment. Indeed, these patients as a group accounted for the differences in overall scores between the missense and nonsense groups. Thus, the impact of specific mutations coupled with possible variation in X-chromosome inactivation must be considered carefully in the derivation of phenotype-genotype correlations. These results emphasize the limitations of such analyses in larger mutation groups, either by type or position.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.20571DOI Listing
April 2004

Rett syndrome in a 47,XXX patient with a de novo MECP2 mutation.

Am J Med Genet A 2003 Oct;122A(3):223-6

Department of Human Genetics, UCLA School of Medicine, Los Angeles, California, USA.

Rett syndrome is caused by mutation in MECP2, a gene located on Xq28 and subject to X-inactivation. MECP2 encodes methyl CpG-binding protein 2, a widely expressed transcriptional repressor of methylated DNA. Mutations in MECP2 are primarily de novo events in the male germ line and thus lead to an excess of affected females. Here we report the identification of a unique 47,XXX girl with relatively mild atypical Rett syndrome leading initially to a diagnosis of infantile autism with regression. Mutation analysis of the MECP2 gene identified a de novo MECP2 mutation, L100V. Examination of a panel of X-linked microsatellite markers indicated that her supernumerary X chromosome is maternally derived. X-inactivation patterns were determined by analysis of methylation of the androgen receptor locus, and indicated preferential inactivation of her paternal allele. The parental origin of her MECP2 mutation could not be determined because she was uninformative for intronic polymorphisms flanking her mutation. This is the first reported case of sex chromosome trisomy and MECP2 mutation in a female, and it illustrates the importance of allele dosage on the severity of Rett syndrome phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.20320DOI Listing
October 2003

The phenotypic consequences of MECP2 mutations extend beyond Rett syndrome.

Ment Retard Dev Disabil Res Rev 2002 ;8(2):94-8

Departments of Human Genetics, Mental Retardation Research Center, University of California, Los Angeles, 695 Chales Young Drive South, Los Angeles California, USA.

Although MECP2 was initially identified as the causative gene in classic Rett syndrome (RTT), the gene has now been implicated in several phenotypes that extend well beyond the clinically defined disorder. MECP2 mutations have been found in people with various disorders, including neonatal onset encephalopathy, X-linked recessive mental retardation (MRX), classic and atypical RTT, autism, and Angelman syndrome, as well as mildly affected females and normal carrier females. To make matters more complex, in approximately 20% of classic sporadic RTT cases and more than 50% of affected sister pairs, no mutation in MECP2 has been found. X-chromosome inactivation patterns can clearly affect the phenotypic expression in females, while the effect of the type and position of the mutation is more apparent in the broader phenotype than in RTT. Both males and females are at risk, although an excess of paternally derived mutations are found in most cases of classic RTT. Thus, because of the range of disparate phenotypes, the gene may account for a relatively large portion of mental retardation in the population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mrdd.10023DOI Listing
September 2002