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Rodan LH, Spillmann RC, Kurata HT, Lamothe SM, Maghera J, Jamra RA, Alkelai A, Antonarakis SE, Atallah I, Bar-Yosef O, Bilan F, Bjorgo K, Blanc X, Van Bogaert P, Bolkier Y, Burrage LC, Christ BU, Granadillo JL, Dickson P, Donald KA, Dubourg C, Eliyahu A, Emrick L, Engleman K, Gonfiantini MV, Good JM, Kalser J, Kloeckner C, Lachmeijer G, Macchiaiolo M, Nicita F, Odent S, O'Heir E, Ortiz-Gonzalez X, Pacio-Miguez M, Palomares-Bralo M, Pena L, Platzer K, Quinodoz M, Ranza E, Rosenfeld JA, Roulet-Perez E, Santani A, Santos-Simarro F, Pode-Shakked B, Skraban C, Slaugh R, Superti-Furga A, Thiffault I, van Jaabrsveld RH, Vincent M, Wang HG, Zacher P, Rush E, Pitt GS, Au PYB, Shashi V. Phenotypic expansion of CACNA1C-associated disorders to include isolated neurological manifestations. Genet Med 2021; 23:1922-1932. [PMID: 34163037 PMCID: PMC8488020 DOI: 10.1038/s41436-021-01232-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 05/14/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE CACNA1C encodes the alpha-1-subunit of a voltage-dependent L-type calcium channel expressed in human heart and brain. Heterozygous variants in CACNA1C have previously been reported in association with Timothy syndrome and long QT syndrome. Several case reports have suggested that CACNA1C variation may also be associated with a primarily neurological phenotype. METHODS We describe 25 individuals from 22 families with heterozygous variants in CACNA1C, who present with predominantly neurological manifestations. RESULTS Fourteen individuals have de novo, nontruncating variants and present variably with developmental delays, intellectual disability, autism, hypotonia, ataxia, and epilepsy. Functional studies of a subgroup of missense variants via patch clamp experiments demonstrated differential effects on channel function in vitro, including loss of function (p.Leu1408Val), neutral effect (p.Leu614Arg), and gain of function (p.Leu657Phe, p.Leu614Pro). The remaining 11 individuals from eight families have truncating variants in CACNA1C. The majority of these individuals have expressive language deficits, and half have autism. CONCLUSION We expand the phenotype associated with CACNA1C variants to include neurodevelopmental abnormalities and epilepsy, in the absence of classic features of Timothy syndrome or long QT syndrome.
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Cleynen I, Engchuan W, Hestand MS, Heung T, Holleman AM, Johnston HR, Monfeuga T, McDonald-McGinn DM, Gur RE, Morrow BE, Swillen A, Vorstman JAS, Bearden CE, Chow EWC, van den Bree M, Emanuel BS, Vermeesch JR, Warren ST, Owen MJ, Chopra P, Cutler DJ, Duncan R, Kotlar AV, Mulle JG, Voss AJ, Zwick ME, Diacou A, Golden A, Guo T, Lin JR, Wang T, Zhang Z, Zhao Y, Marshall C, Merico D, Jin A, Lilley B, Salmons HI, Tran O, Holmans P, Pardinas A, Walters JTR, Demaerel W, Boot E, Butcher NJ, Costain GA, Lowther C, Evers R, van Amelsvoort TAMJ, van Duin E, Vingerhoets C, Breckpot J, Devriendt K, Vergaelen E, Vogels A, Crowley TB, McGinn DE, Moss EM, Sharkus RJ, Unolt M, Zackai EH, Calkins ME, Gallagher RS, Gur RC, Tang SX, Fritsch R, Ornstein C, Repetto GM, Breetvelt E, Duijff SN, Fiksinski A, Moss H, Niarchou M, Murphy KC, Prasad SE, Daly EM, Gudbrandsen M, Murphy CM, Murphy DG, Buzzanca A, Fabio FD, Digilio MC, Pontillo M, Marino B, Vicari S, Coleman K, Cubells JF, Ousley OY, Carmel M, Gothelf D, Mekori-Domachevsky E, Michaelovsky E, Weinberger R, Weizman A, Kushan L, Jalbrzikowski M, Armando M, Eliez S, Sandini C, Schneider M, Béna FS, Antshel KM, Fremont W, Kates WR, Belzeaux R, Busa T, Philip N, Campbell LE, McCabe KL, Hooper SR, Schoch K, Shashi V, Simon TJ, Tassone F, Arango C, Fraguas D, García-Miñaúr S, Morey-Canyelles J, Rosell J, Suñer DH, Raventos-Simic J, Epstein MP, Williams NM, Bassett AS. Genetic contributors to risk of schizophrenia in the presence of a 22q11.2 deletion. Mol Psychiatry 2021; 26:4496-4510. [PMID: 32015465 PMCID: PMC7396297 DOI: 10.1038/s41380-020-0654-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 11/01/2019] [Accepted: 01/16/2020] [Indexed: 12/17/2022]
Abstract
Schizophrenia occurs in about one in four individuals with 22q11.2 deletion syndrome (22q11.2DS). The aim of this International Brain and Behavior 22q11.2DS Consortium (IBBC) study was to identify genetic factors that contribute to schizophrenia, in addition to the ~20-fold increased risk conveyed by the 22q11.2 deletion. Using whole-genome sequencing data from 519 unrelated individuals with 22q11.2DS, we conducted genome-wide comparisons of common and rare variants between those with schizophrenia and those with no psychotic disorder at age ≥25 years. Available microarray data enabled direct comparison of polygenic risk for schizophrenia between 22q11.2DS and independent population samples with no 22q11.2 deletion, with and without schizophrenia (total n = 35,182). Polygenic risk for schizophrenia within 22q11.2DS was significantly greater for those with schizophrenia (padj = 6.73 × 10-6). Novel reciprocal case-control comparisons between the 22q11.2DS and population-based cohorts showed that polygenic risk score was significantly greater in individuals with psychotic illness, regardless of the presence of the 22q11.2 deletion. Within the 22q11.2DS cohort, results of gene-set analyses showed some support for rare variants affecting synaptic genes. No common or rare variants within the 22q11.2 deletion region were significantly associated with schizophrenia. These findings suggest that in addition to the deletion conferring a greatly increased risk to schizophrenia, the risk is higher when the 22q11.2 deletion and common polygenic risk factors that contribute to schizophrenia in the general population are both present.
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Cope H, Barseghyan H, Bhattacharya S, Fu Y, Hoppman N, Marcou C, Walley N, Rehder C, Deak K, Alkelai A, Vilain E, Shashi V. Detection of a mosaic CDKL5 deletion and inversion by optical genome mapping ends an exhaustive diagnostic odyssey. Mol Genet Genomic Med 2021; 9:e1665. [PMID: 33955715 PMCID: PMC8372083 DOI: 10.1002/mgg3.1665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Currently available structural variant (SV) detection methods do not span the complete spectrum of disease-causing SVs. Optical genome mapping (OGM), an emerging technology with the potential to resolve diagnostic dilemmas, was performed to investigate clinically-relevant SVs in a 4-year-old male with an epileptic encephalopathy of undiagnosed molecular origin. METHODS OGM was utilized to image long, megabase-size DNA molecules, fluorescently labeled at specific sequence motifs throughout the genome with high sensitivity for detection of SVs greater than 500 bp in size. OGM results were confirmed in a CLIA-certified laboratory via mate-pair sequencing. RESULTS OGM identified a mosaic, de novo 90 kb deletion and inversion on the X chromosome disrupting the CDKL5 gene. Detection of the mosaic deletion, which had been previously undetected by chromosomal microarray, an infantile epilepsy panel including exon-level microarray for CDKL5, exome sequencing as well as genome sequencing, resulted in a diagnosis of X-linked dominant early infantile epileptic encephalopathy-2. CONCLUSION OGM affords an effective technology for the detection of SVs, especially those that are mosaic, since these remain difficult to detect with current NGS technologies and with conventional chromosomal microarrays. Further research in undiagnosed populations with OGM is warranted.
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Parenti I, Lehalle D, Nava C, Torti E, Leitão E, Person R, Mizuguchi T, Matsumoto N, Kato M, Nakamura K, de Man SA, Cope H, Shashi V, Friedman J, Joset P, Steindl K, Rauch A, Muffels I, van Hasselt PM, Petit F, Smol T, Le Guyader G, Bilan F, Sorlin A, Vitobello A, Philippe C, van de Laar IMBH, van Slegtenhorst MA, Campeau PM, Au PYB, Nakashima M, Saitsu H, Yamamoto T, Nomura Y, Louie RJ, Lyons MJ, Dobson A, Plomp AS, Motazacker MM, Kaiser FJ, Timberlake AT, Fuchs SA, Depienne C, Mignot C. Missense and truncating variants in CHD5 in a dominant neurodevelopmental disorder with intellectual disability, behavioral disturbances, and epilepsy. Hum Genet 2021; 140:1109-1120. [PMID: 33944996 PMCID: PMC8197709 DOI: 10.1007/s00439-021-02283-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/15/2021] [Indexed: 12/27/2022]
Abstract
Located in the critical 1p36 microdeletion region, the chromodomain helicase DNA-binding protein 5 (CHD5) gene encodes a subunit of the nucleosome remodeling and deacetylation (NuRD) complex required for neuronal development. Pathogenic variants in six of nine chromodomain (CHD) genes cause autosomal dominant neurodevelopmental disorders, while CHD5-related disorders are still unknown. Thanks to GeneMatcher and international collaborations, we assembled a cohort of 16 unrelated individuals harboring heterozygous CHD5 variants, all identified by exome sequencing. Twelve patients had de novo CHD5 variants, including ten missense and two splice site variants. Three familial cases had nonsense or missense variants segregating with speech delay, learning disabilities, and/or craniosynostosis. One patient carried a frameshift variant of unknown inheritance due to unavailability of the father. The most common clinical features included language deficits (81%), behavioral symptoms (69%), intellectual disability (64%), epilepsy (62%), and motor delay (56%). Epilepsy types were variable, with West syndrome observed in three patients, generalized tonic-clonic seizures in two, and other subtypes observed in one individual each. Our findings suggest that, in line with other CHD-related disorders, heterozygous CHD5 variants are associated with a variable neurodevelopmental syndrome that includes intellectual disability with speech delay, epilepsy, and behavioral problems as main features.
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Luo X, Schoch K, Jangam SV, Bhavana VH, Graves HK, Kansagra S, Jasien JM, Stong N, Keren B, Mignot C, Ravelli C, Bellen HJ, Wangler MF, Shashi V, Yamamoto S. Rare deleterious de novo missense variants in Rnf2/Ring2 are associated with a neurodevelopmental disorder with unique clinical features. Hum Mol Genet 2021; 30:1283-1292. [PMID: 33864376 PMCID: PMC8255132 DOI: 10.1093/hmg/ddab110] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/09/2021] [Accepted: 04/14/2021] [Indexed: 01/16/2023] Open
Abstract
The Polycomb group (PcG) gene RNF2 (RING2) encodes a catalytic subunit of the Polycomb repressive complex 1 (PRC1), an evolutionarily conserved machinery that post-translationally modifies chromatin to maintain epigenetic transcriptional repressive states of target genes including Hox genes. Here, we describe two individuals, each with rare de novo missense variants in RNF2. Their phenotypes include intrauterine growth retardation, severe intellectual disabilities, behavioral problems, seizures, feeding difficulties and dysmorphic features. Population genomics data suggest that RNF2 is highly constrained for loss-of-function (LoF) and missense variants, and both p.R70H and p.S82R variants have not been reported to date. Structural analyses of the two alleles indicate that these changes likely impact the interaction between RNF2 and BMI1, another PRC1 subunit or its substrate Histone H2A, respectively. Finally, we provide functional data in Drosophila that these two missense variants behave as LoF alleles in vivo. The evidence provide support for deleterious alleles in RNF2 being associated with a new and recognizable genetic disorder. This tentative gene-disease association in addition to the 12 previously identified disorders caused by PcG genes attests to the importance of these chromatin regulators in Mendelian disorders.
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Bowles B, Ferrer A, Nishimura CJ, Pinto E Vairo F, Rey T, Leheup B, Sullivan J, Schoch K, Stong N, Agolini E, Cocciadiferro D, Williams A, Cummings A, Loddo S, Genovese S, Roadhouse C, McWalter K, Wentzensen IM, Li C, Babovic-Vuksanovic D, Lanpher BC, Dentici ML, Ankala A, Hamm JA, Dallapiccola B, Radio FC, Shashi V, Gérard B, Bloch-Zupan A, Smith RJ, Klee EW. TSPEAR variants are primarily associated with ectodermal dysplasia and tooth agenesis but not hearing loss: A novel cohort study. Am J Med Genet A 2021; 185:2417-2433. [PMID: 34042254 PMCID: PMC8361973 DOI: 10.1002/ajmg.a.62347] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 04/12/2021] [Accepted: 04/22/2021] [Indexed: 12/30/2022]
Abstract
Biallelic loss‐of‐function variants in the thrombospondin‐type laminin G domain and epilepsy‐associated repeats (TSPEAR) gene have recently been associated with ectodermal dysplasia and hearing loss. The first reports describing a TSPEAR disease association identified this gene is a cause of nonsyndromic hearing loss, but subsequent reports involving additional affected families have questioned this evidence and suggested a stronger association with ectodermal dysplasia. To clarify genotype–phenotype associations for TSPEAR variants, we characterized 13 individuals with biallelic TSPEAR variants. Individuals underwent either exome sequencing or panel‐based genetic testing. Nearly all of these newly reported individuals (11/13) have phenotypes that include tooth agenesis or ectodermal dysplasia, while three newly reported individuals have hearing loss. Of the individuals displaying hearing loss, all have additional variants in other hearing‐loss‐associated genes, specifically TMPRSS3, GJB2, and GJB6, that present competing candidates for their hearing loss phenotype. When presented alongside previous reports, the overall evidence supports the association of TSPEAR variants with ectodermal dysplasia and tooth agenesis features but creates significant doubt as to whether TSPEAR variants are a monogenic cause of hearing loss. Further functional evidence is needed to evaluate this phenotypic association.
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Dias C, Pfundt R, Kleefstra T, Shuurs-Hoeijmakers J, Boon EMJ, van Hagen JM, Zwijnenburg P, Weiss MM, Keren B, Mignot C, Isapof A, Weiss K, Hershkovitz T, Iascone M, Maitz S, Feichtinger RG, Kotzot D, Mayr JA, Ben-Omran T, Mahmoud L, Pais LS, Walsh CA, Shashi V, Sullivan JA, Stong N, Lecoquierre F, Guerrot AM, Charollais A, Rodan LH. De novo variants in TCF7L2 are associated with a syndromic neurodevelopmental disorder. Am J Med Genet A 2021; 185:2384-2390. [PMID: 34003604 DOI: 10.1002/ajmg.a.62254] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/25/2021] [Accepted: 04/24/2021] [Indexed: 01/21/2023]
Abstract
TCF7L2 encodes transcription factor 7-like 2 (OMIM 602228), a key mediator of the evolutionary conserved canonical Wnt signaling pathway. Although several large-scale sequencing studies have implicated TCF7L2 in intellectual disability and autism, both the genetic mechanism and clinical phenotype have remained incompletely characterized. We present here a comprehensive genetic and phenotypic description of 11 individuals who have been identified to carry de novo variants in TCF7L2, both truncating and missense. Missense variation is clustered in or near a high mobility group box domain, involving this region in these variants' pathogenicity. All affected individuals present with developmental delays in childhood, but most ultimately achieved normal intelligence or had only mild intellectual disability. Myopia was present in approximately half of the individuals, and some individuals also possessed dysmorphic craniofacial features, orthopedic abnormalities, or neuropsychiatric comorbidities including autism and attention-deficit/hyperactivity disorder (ADHD). We thus present an initial clinical and genotypic spectrum associated with variation in TCF7L2, which will be important in informing both medical management and future research.
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Cappuccio G, Ceccatelli Berti C, Baruffini E, Sullivan J, Shashi V, Jewett T, Stamper T, Maitz S, Canonico F, Revah-Politi A, Kupchik GS, Anyane-Yeboa K, Aggarwal V, Benneche A, Bratland E, Berland S, D'Arco F, Alves CA, Vanderver A, Longo D, Bertini E, Torella A, Nigro V, D'Amico A, van der Knaap MS, Goffrini P, Brunetti-Pierri N. Bi-allelic KARS1 pathogenic variants affecting functions of cytosolic and mitochondrial isoforms are associated with a progressive and multisystem disease. Hum Mutat 2021; 42:745-761. [PMID: 33942428 PMCID: PMC8251883 DOI: 10.1002/humu.24210] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/10/2021] [Accepted: 04/07/2021] [Indexed: 12/12/2022]
Abstract
KARS1 encodes a lysyl‐transfer RNA synthetase (LysRS) that links lysine to its cognate transfer RNA. Two different KARS1 isoforms exert functional effects in cytosol and mitochondria. Bi‐allelic pathogenic variants in KARS1 have been associated to sensorineural hearing and visual loss, neuropathy, seizures, and leukodystrophy. We report the clinical, biochemical, and neuroradiological features of nine individuals with KARS1‐related disorder carrying 12 different variants with nine of them being novel. The consequences of these variants on the cytosol and/or mitochondrial LysRS were functionally validated in yeast mutants. Most cases presented with severe neurological features including congenital and progressive microcephaly, seizures, developmental delay/intellectual disability, and cerebral atrophy. Oculo‐motor dysfunction and immuno‐hematological problems were present in six and three cases, respectively. A yeast growth defect of variable severity was detected for most variants on both cytosolic and mitochondrial isoforms. The detrimental effects of two variants on yeast growth were partially rescued by lysine supplementation. Congenital progressive microcephaly, oculo‐motor dysfunction, and immuno‐hematological problems are emerging phenotypes in KARS1‐related disorder. The data in yeast emphasize the role of both mitochondrial and cytosolic isoforms in the pathogenesis of KARS1‐related disorder and supports the therapeutic potential of lysine supplementation at least in a subset of patients.
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Rehder C, Bean LJH, Bick D, Chao E, Chung W, Das S, O'Daniel J, Rehm H, Shashi V, Vincent LM. Next-generation sequencing for constitutional variants in the clinical laboratory, 2021 revision: a technical standard of the American College of Medical Genetics and Genomics (ACMG). Genet Med 2021; 23:1399-1415. [PMID: 33927380 DOI: 10.1038/s41436-021-01139-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 12/17/2022] Open
Abstract
Next-generation sequencing (NGS) technologies are now established in clinical laboratories as a primary testing modality in genomic medicine. These technologies have reduced the cost of large-scale sequencing by several orders of magnitude. It is now cost-effective to analyze an individual with disease-targeted gene panels, exome sequencing, or genome sequencing to assist in the diagnosis of a wide array of clinical scenarios. While clinical validation and use of NGS in many settings is established, there are continuing challenges as technologies and the associated informatics evolve. To assist clinical laboratories with the validation of NGS methods and platforms, the ongoing monitoring of NGS testing to ensure quality results, and the interpretation and reporting of variants found using these technologies, the American College of Medical Genetics and Genomics (ACMG) has developed the following technical standards.
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Moya-Mendez ME, Mueller DM, Pratt M, Bonner M, Elliott C, Hunanyan A, Kucera G, Bock C, Prange L, Jasien J, Keough K, Shashi V, McDonald M, Mikati MA. Early onset severe ATP1A2 epileptic encephalopathy: Clinical characteristics and underlying mutations. Epilepsy Behav 2021; 116:107732. [PMID: 33493807 PMCID: PMC7940561 DOI: 10.1016/j.yebeh.2020.107732] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/09/2020] [Accepted: 12/20/2020] [Indexed: 01/26/2023]
Abstract
BACKGROUND ATP1A2 mutations cause hemiplegic migraine with or without epilepsy or acute reversible encephalopathy. Typical onset is in adulthood or older childhood without subsequent severe long-term developmental impairments. AIM We aimed to describe the manifestations of early onset severe ATP1A2-related epileptic encephalopathy and its underlying mutations in a cohort of seven patients. METHODS A retrospective chart review of a cohort of seven patients was conducted. Response to open-label memantine therapy, used off-label due to its NMDA receptor antagonist effects, was assessed by the Global Rating Scale of Change (GRSC) and Clinical Global Impression Scale of Improvement (CGI-I) methodologies. Molecular modeling was performed using PyMol program. RESULTS Patients (age 2.5-20 years) had symptom onset at an early age (6 days-1 year). Seizures were either focal or generalized. Common features were: drug resistance, recurrent status epilepticus, etc., severe developmental delay with episodes of acute severe encephalopathy often with headaches, dystonias, hemiplegias, seizures, and developmental regression. All had variants predicted to be disease causing (p.Ile293Met, p.Glu1000Lys, c.1017+5G>A, p.Leu809Arg, and 3 patients with p.Met813Lys). Modeling revealed that mutations interfered with ATP1A2 ion binding and translocation sites. Memantine, given to five, was tolerated in all (mean treatment: 2.3 years, range 6 weeks-4.8 years) with some improvements reported in all five. CONCLUSIONS Our observations describe a distinctive clinical profile of seven unrelated probands with early onset severe ATP1A2-related epileptic encephalopathy, provide insights into structure-function relationships of ATP1A2 mutations, and support further studies of NMDAR antagonist therapy in ATP1A2-encephalopathy.
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Weng PL, Majmundar AJ, Khan K, Lim TY, Shril S, Jin G, Musgrove J, Wang M, Ahram DF, Aggarwal VS, Bier LE, Heinzen EL, Onuchic-Whitford AC, Mann N, Buerger F, Schneider R, Deutsch K, Kitzler TM, Klämbt V, Kolb A, Mao Y, Moufawad El Achkar C, Mitrotti A, Martino J, Beck BB, Altmüller J, Benz MR, Yano S, Mikati MA, Gunduz T, Cope H, Shashi V, Trachtman H, Bodria M, Caridi G, Pisani I, Fiaccadori E, AbuMaziad AS, Martinez-Agosto JA, Yadin O, Zuckerman J, Kim A, John-Kroegel U, Tyndall AV, Parboosingh JS, Innes AM, Bierzynska A, Koziell AB, Muorah M, Saleem MA, Hoefele J, Riedhammer KM, Gharavi AG, Jobanputra V, Pierce-Hoffman E, Seaby EG, O'Donnell-Luria A, Rehm HL, Mane S, D'Agati VD, Pollak MR, Ghiggeri GM, Lifton RP, Goldstein DB, Davis EE, Hildebrandt F, Sanna-Cherchi S. De novo TRIM8 variants impair its protein localization to nuclear bodies and cause developmental delay, epilepsy, and focal segmental glomerulosclerosis. Am J Hum Genet 2021; 108:357-367. [PMID: 33508234 PMCID: PMC7895901 DOI: 10.1016/j.ajhg.2021.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) is the main pathology underlying steroid-resistant nephrotic syndrome (SRNS) and a leading cause of chronic kidney disease. Monogenic forms of pediatric SRNS are predominantly caused by recessive mutations, while the contribution of de novo variants (DNVs) to this trait is poorly understood. Using exome sequencing (ES) in a proband with FSGS/SRNS, developmental delay, and epilepsy, we discovered a nonsense DNV in TRIM8, which encodes the E3 ubiquitin ligase tripartite motif containing 8. To establish whether TRIM8 variants represent a cause of FSGS, we aggregated exome/genome-sequencing data for 2,501 pediatric FSGS/SRNS-affected individuals and 48,556 control subjects, detecting eight heterozygous TRIM8 truncating variants in affected subjects but none in control subjects (p = 3.28 × 10-11). In all six cases with available parental DNA, we demonstrated de novo inheritance (p = 2.21 × 10-15). Reverse phenotyping revealed neurodevelopmental disease in all eight families. We next analyzed ES from 9,067 individuals with epilepsy, yielding three additional families with truncating TRIM8 variants. Clinical review revealed FSGS in all. All TRIM8 variants cause protein truncation clustering within the last exon between residues 390 and 487 of the 551 amino acid protein, indicating a correlation between this syndrome and loss of the TRIM8 C-terminal region. Wild-type TRIM8 overexpressed in immortalized human podocytes and neuronal cells localized to nuclear bodies, while constructs harboring patient-specific variants mislocalized diffusely to the nucleoplasm. Co-localization studies demonstrated that Gemini and Cajal bodies frequently abut a TRIM8 nuclear body. Truncating TRIM8 DNVs cause a neuro-renal syndrome via aberrant TRIM8 localization, implicating nuclear bodies in FSGS and developmental brain disease.
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Schoch K, Esteves C, Bican A, Spillmann R, Cope H, McConkie-Rosell A, Walley N, Fernandez L, Kohler JN, Bonner D, Reuter C, Stong N, Mulvihill JJ, Novacic D, Wolfe L, Abdelbaki A, Toro C, Tifft C, Malicdan M, Gahl W, Liu P, Newman J, Goldstein DB, Hom J, Sampson J, Wheeler MT, Cogan J, Bernstein JA, Adams DR, McCray AT, Shashi V. Clinical sites of the Undiagnosed Diseases Network: unique contributions to genomic medicine and science. Genet Med 2021; 23:259-271. [PMID: 33093671 PMCID: PMC7867619 DOI: 10.1038/s41436-020-00984-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The NIH Undiagnosed Diseases Network (UDN) evaluates participants with disorders that have defied diagnosis, applying personalized clinical and genomic evaluations and innovative research. The clinical sites of the UDN are essential to advancing the UDN mission; this study assesses their contributions relative to standard clinical practices. METHODS We analyzed retrospective data from four UDN clinical sites, from July 2015 to September 2019, for diagnoses, new disease gene discoveries and the underlying investigative methods. RESULTS Of 791 evaluated individuals, 231 received 240 diagnoses and 17 new disease-gene associations were recognized. Straightforward diagnoses on UDN exome and genome sequencing occurred in 35% (84/240). We considered these tractable in standard clinical practice, although genome sequencing is not yet widely available clinically. The majority (156/240, 65%) required additional UDN-driven investigations, including 90 diagnoses that occurred after prior nondiagnostic exome sequencing and 45 diagnoses (19%) that were nongenetic. The UDN-driven investigations included complementary/supplementary phenotyping, innovative analyses of genomic variants, and collaborative science for functional assays and animal modeling. CONCLUSION Investigations driven by the clinical sites identified diagnostic and research paradigms that surpass standard diagnostic processes. The new diagnoses, disease gene discoveries, and delineation of novel disorders represent a model for genomic medicine and science.
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Klöckner C, Sticht H, Zacher P, Popp B, Babcock HE, Bakker DP, Barwick K, Bonfert MV, Bönnemann CG, Brilstra EH, Chung WK, Clarke AJ, Devine P, Donkervoort S, Fraser JL, Friedman J, Gates A, Ghoumid J, Hobson E, Horvath G, Keller-Ramey J, Keren B, Kurian MA, Lee V, Leppig KA, Lundgren J, McDonald MT, McLaughlin HM, McTague A, Mefford HC, Mignot C, Mikati MA, Nava C, Raymond FL, Sampson JR, Sanchis-Juan A, Shashi V, Shieh JTC, Shinawi M, Slavotinek A, Stödberg T, Stong N, Sullivan JA, Taylor AC, Toler TL, van den Boogaard MJ, van der Crabben SN, van Gassen KLI, van Jaarsveld RH, Van Ziffle J, Wadley AF, Wagner M, Wigby K, Wortmann SB, Zarate YA, Møller RS, Lemke JR, Platzer K. De novo variants in SNAP25 cause an early-onset developmental and epileptic encephalopathy. Genet Med 2020; 23:653-660. [PMID: 33299146 DOI: 10.1038/s41436-020-01020-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE This study aims to provide a comprehensive description of the phenotypic and genotypic spectrum of SNAP25 developmental and epileptic encephalopathy (SNAP25-DEE) by reviewing newly identified and previously reported individuals. METHODS Individuals harboring heterozygous missense or loss-of-function variants in SNAP25 were assembled through collaboration with international colleagues, matchmaking platforms, and literature review. For each individual, detailed phenotyping, classification, and structural modeling of the identified variant were performed. RESULTS The cohort comprises 23 individuals with pathogenic or likely pathogenic de novo variants in SNAP25. Intellectual disability and early-onset epilepsy were identified as the core symptoms of SNAP25-DEE, with recurrent findings of movement disorders, cerebral visual impairment, and brain atrophy. Structural modeling for all variants predicted possible functional defects concerning SNAP25 or impaired interaction with other components of the SNARE complex. CONCLUSION We provide a comprehensive description of SNAP25-DEE with intellectual disability and early-onset epilepsy mostly occurring before the age of two years. These core symptoms and additional recurrent phenotypes show an overlap to genes encoding other components or associated proteins of the SNARE complex such as STX1B, STXBP1, or VAMP2. Thus, these findings advance the concept of a group of neurodevelopmental disorders that may be termed "SNAREopathies."
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Davies RW, Fiksinski AM, Breetvelt EJ, Williams NM, Hooper SR, Monfeuga T, Bassett AS, Owen MJ, Gur RE, Morrow BE, McDonald-McGinn DM, Swillen A, Chow EWC, van den Bree M, Emanuel BS, Vermeesch JR, van Amelsvoort T, Arango C, Armando M, Campbell LE, Cubells JF, Eliez S, Garcia-Minaur S, Gothelf D, Kates WR, Murphy KC, Murphy CM, Murphy DG, Philip N, Repetto GM, Shashi V, Simon TJ, Suñer DH, Vicari S, Scherer SW, Bearden CE, Vorstman JAS. Using common genetic variation to examine phenotypic expression and risk prediction in 22q11.2 deletion syndrome. Nat Med 2020; 26:1912-1918. [PMID: 33169016 PMCID: PMC7975627 DOI: 10.1038/s41591-020-1103-1] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 09/14/2020] [Indexed: 02/06/2023]
Abstract
The 22q11.2 deletion syndrome (22q11DS) is associated with a 20-25% risk of schizophrenia. In a cohort of 962 individuals with 22q11DS, we examined the shared genetic basis between schizophrenia and schizophrenia-related early trajectory phenotypes: sub-threshold symptoms of psychosis, low baseline intellectual functioning and cognitive decline. We studied the association of these phenotypes with two polygenic scores, derived for schizophrenia and intelligence, and evaluated their use for individual risk prediction in 22q11DS. Polygenic scores were not only associated with schizophrenia and baseline intelligence quotient (IQ), respectively, but schizophrenia polygenic score was also significantly associated with cognitive (verbal IQ) decline and nominally associated with sub-threshold psychosis. Furthermore, in comparing the tail-end deciles of the schizophrenia and IQ polygenic score distributions, 33% versus 9% of individuals with 22q11DS had schizophrenia, and 63% versus 24% of individuals had intellectual disability. Collectively, these data show a shared genetic basis for schizophrenia and schizophrenia-related phenotypes and also highlight the future potential of polygenic scores for risk stratification among individuals with highly, but incompletely, penetrant genetic variants.
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Brunet T, McWalter K, Mayerhanser K, Anbouba GM, Armstrong-Javors A, Bader I, Baugh E, Begtrup A, Bupp CP, Callewaert BL, Cereda A, Cousin MA, Del Rey Jimenez JC, Demmer L, Dsouza NR, Fleischer N, Gavrilova RH, Ghate S, Graf E, Green A, Green SR, Iascone M, Kdissa A, Klee D, Klee EW, Lancaster E, Lindstrom K, Mayr JA, McEntagart M, Meeks NJL, Mittag D, Moore H, Olsen AK, Ortiz D, Parsons G, Pena LDM, Person RE, Punj S, Ramos-Rivera GA, Sacoto MJG, Bradley Schaefer G, Schnur RE, Scott TM, Scott DA, Serbinski CR, Shashi V, Siu VM, Stadheim BF, Sullivan JA, Švantnerová J, Velsher L, Wargowski DS, Wentzensen IM, Wieczorek D, Winkelmann J, Yap P, Zech M, Zimmermann MT, Meitinger T, Distelmaier F, Wagner M. Defining the genotypic and phenotypic spectrum of X-linked MSL3-related disorder. Genet Med 2020; 23:384-395. [PMID: 33173220 PMCID: PMC7862064 DOI: 10.1038/s41436-020-00993-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/23/2020] [Indexed: 12/01/2022] Open
Abstract
Purpose We sought to delineate the genotypic and phenotypic spectrum of female and male individuals with X-linked, MSL3-related disorder (Basilicata–Akhtar syndrome). Methods Twenty-five individuals (15 males, 10 females) with causative variants in MSL3 were ascertained through exome or genome sequencing at ten different sequencing centers. Results We identified multiple variant types in MSL3 (ten nonsense, six frameshift, four splice site, three missense, one in-frame-deletion, one multi-exon deletion), most proven to be de novo, and clustering in the terminal eight exons suggesting that truncating variants in the first five exons might be compensated by an alternative MSL3 transcript. Three-dimensional modeling of missense and splice variants indicated that these have a deleterious effect. The main clinical findings comprised developmental delay and intellectual disability ranging from mild to severe. Autism spectrum disorder, muscle tone abnormalities, and macrocephaly were common as well as hearing impairment and gastrointestinal problems. Hypoplasia of the cerebellar vermis emerged as a consistent magnetic resonance image (MRI) finding. Females and males were equally affected. Using facial analysis technology, a recognizable facial gestalt was determined. Conclusion Our aggregated data illustrate the genotypic and phenotypic spectrum of X-linked, MSL3-related disorder (Basilicata–Akhtar syndrome). Our cohort improves the understanding of disease related morbidity and allows us to propose detailed surveillance guidelines for affected individuals.
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Lenaerts L, Reynhout S, Verbinnen I, Laumonnier F, Toutain A, Bonnet-Brilhault F, Hoorne Y, Joss S, Chassevent AK, Smith-Hicks C, Loeys B, Joset P, Steindl K, Rauch A, Mehta SG, Chung WK, Devriendt K, Holder SE, Jewett T, Baldwin LM, Wilson WG, Towner S, Srivastava S, Johnson HF, Daumer-Haas C, Baethmann M, Ruiz A, Gabau E, Jain V, Varghese V, Al-Beshri A, Fulton S, Wechsberg O, Orenstein N, Prescott K, Childs AM, Faivre L, Moutton S, Sullivan JA, Shashi V, Koudijs SM, Heijligers M, Kivuva E, McTague A, Male A, van Ierland Y, Plecko B, Maystadt I, Hamid R, Hannig VL, Houge G, Janssens V. The broad phenotypic spectrum of PPP2R1A-related neurodevelopmental disorders correlates with the degree of biochemical dysfunction. Genet Med 2020; 23:352-362. [PMID: 33106617 PMCID: PMC7862067 DOI: 10.1038/s41436-020-00981-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 12/31/2022] Open
Abstract
Purpose Neurodevelopmental disorders (NDD) caused by protein phosphatase 2A (PP2A) dysfunction have mainly been associated with de novo variants in PPP2R5D and PPP2CA, and more rarely in PPP2R1A. Here, we aimed to better understand the latter by characterizing 30 individuals with de novo and often recurrent variants in this PP2A scaffolding Aα subunit. Methods Most cases were identified through routine clinical diagnostics. Variants were biochemically characterized for phosphatase activity and interaction with other PP2A subunits. Results We describe 30 individuals with 16 different variants in PPP2R1A, 21 of whom had variants not previously reported. The severity of developmental delay ranged from mild learning problems to severe intellectual disability (ID) with or without epilepsy. Common features were language delay, hypotonia, and hypermobile joints. Macrocephaly was only seen in individuals without B55α subunit-binding deficit, and these patients had less severe ID and no seizures. Biochemically more disruptive variants with impaired B55α but increased striatin binding were associated with profound ID, epilepsy, corpus callosum hypoplasia, and sometimes microcephaly. Conclusion We significantly expand the phenotypic spectrum of PPP2R1A-related NDD, revealing a broader clinical presentation of the patients and that the functional consequences of the variants are more diverse than previously reported.
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Prange L, Pratt M, Herman K, Schiffmann R, Mueller DM, McLean M, Mendez MM, Walley N, Heinzen EL, Goldstein D, Shashi V, Hunanyan A, Pagadala V, Mikati MA. D-DEMØ, a distinct phenotype caused by ATP1A3 mutations. NEUROLOGY-GENETICS 2020; 6:e466. [PMID: 32802951 PMCID: PMC7413631 DOI: 10.1212/nxg.0000000000000466] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/18/2020] [Indexed: 11/15/2022]
Abstract
Objective To describe a phenotype caused by ATP1A3 mutations, which manifests as dystonia, dysmorphism of the face, encephalopathy with developmental delay, brain MRI abnormalities always including cerebellar hypoplasia, no hemiplegia (Ø) (D-DEMØ), and neonatal onset. Methods Review and analysis of clinical and genetic data. Results Patients shared the above traits and had whole-exome sequencing that showed de novo variants of the ATP1A3 gene, predicted to be disease causing and occurring in regions of the protein critical for pump function. Patient 1 (c.1079C>G, p.Thr360Arg), an 8-year-old girl, presented on day 1 of life with episodic dystonia, complex partial seizures, and facial dysmorphism. MRI of the brain revealed cerebellar hypoplasia. Patient 2 (c.420G>T, p.Gln140His), an 18-year-old man, presented on day 1 of life with hypotonia, tremor, and facial dysmorphism. He later developed dystonia. MRI of the brain revealed cerebellar hypoplasia and, later, further cerebellar volume loss (atrophy). Patient 3 (c.974G>A, Gly325Asp), a 13-year-old girl, presented on day 1 of life with tremor, episodic dystonia, and facial dysmorphism. MRI of the brain showed severe cerebellar hypoplasia. Patient 4 (c.971A>G, p.Glu324Gly), a 14-year-old boy, presented on day 1 of life with tremor, hypotonia, dystonia, nystagmus, facial dysmorphism, and later seizures. MRI of the brain revealed moderate cerebellar hypoplasia. Conclusions D-DEMØ represents an ATP1A3-related phenotype, the observation of which should trigger investigation for ATP1A3 mutations. Our findings, and the presence of multiple distinct ATP1A3-related phenotypes, support the possibility that there are differences in the underlying mechanisms.
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Cope H, Spillmann R, Rosenfeld JA, Brokamp E, Signer R, Schoch K, Kelley EG, Sullivan JA, Macnamara E, Lincoln S, Golden-Grant K, Orengo JP, Clark G, Burrage LC, Posey JE, Punetha J, Robertson A, Cogan J, Phillips JA, Martinez-Agosto J, Shashi V. Missed diagnoses: Clinically relevant lessons learned through medical mysteries solved by the Undiagnosed Diseases Network. Mol Genet Genomic Med 2020; 8:e1397. [PMID: 32730690 PMCID: PMC7549585 DOI: 10.1002/mgg3.1397] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 12/12/2022] Open
Abstract
Background Resources within the Undiagnosed Diseases Network (UDN), such as genome sequencing (GS) and model organisms aid in diagnosis and identification of new disease genes, but are currently difficult to access by clinical providers. While these resources do contribute to diagnoses in many cases, they are not always necessary to reach diagnostic resolution. The UDN experience has been that participants can also receive diagnoses through the thoughtful and customized application of approaches and resources that are readily available in clinical settings. Methods The UDN Genetic Counseling and Testing Working Group collected case vignettes that illustrated how clinically available methods resulted in diagnoses. The case vignettes were classified into three themes; phenotypic considerations, selection of genetic testing, and evaluating exome/GS variants and data. Results We present 12 participants that illustrate how clinical practices such as phenotype‐driven genomic investigations, consideration of variable expressivity, selecting the relevant tissue of interest for testing, utilizing updated testing platforms, and recognition of alternate transcript nomenclature resulted in diagnoses. Conclusion These examples demonstrate that when a diagnosis is elusive, an iterative patient‐specific approach utilizing assessment options available to clinical providers may solve a portion of cases. However, this does require increased provider time commitment, a particular challenge in the current practice of genomics.
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Del Dotto V, Ullah F, Di Meo I, Magini P, Gusic M, Maresca A, Caporali L, Palombo F, Tagliavini F, Baugh EH, Macao B, Szilagyi Z, Peron C, Gustafson MA, Khan K, La Morgia C, Barboni P, Carbonelli M, Valentino ML, Liguori R, Shashi V, Sullivan J, Nagaraj S, El-Dairi M, Iannaccone A, Cutcutache I, Bertini E, Carrozzo R, Emma F, Diomedi-Camassei F, Zanna C, Armstrong M, Page M, Stong N, Boesch S, Kopajtich R, Wortmann S, Sperl W, Davis EE, Copeland WC, Seri M, Falkenberg M, Prokisch H, Katsanis N, Tiranti V, Pippucci T, Carelli V. SSBP1 mutations cause mtDNA depletion underlying a complex optic atrophy disorder. J Clin Invest 2020; 130:108-125. [PMID: 31550240 DOI: 10.1172/jci128514] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 09/19/2019] [Indexed: 01/07/2023] Open
Abstract
Inherited optic neuropathies include complex phenotypes, mostly driven by mitochondrial dysfunction. We report an optic atrophy spectrum disorder, including retinal macular dystrophy and kidney insufficiency leading to transplantation, associated with mitochondrial DNA (mtDNA) depletion without accumulation of multiple deletions. By whole-exome sequencing, we identified mutations affecting the mitochondrial single-strand binding protein (SSBP1) in 4 families with dominant and 1 with recessive inheritance. We show that SSBP1 mutations in patient-derived fibroblasts variably affect the amount of SSBP1 protein and alter multimer formation, but not the binding to ssDNA. SSBP1 mutations impaired mtDNA, nucleoids, and 7S-DNA amounts as well as mtDNA replication, affecting replisome machinery. The variable mtDNA depletion in cells was reflected in severity of mitochondrial dysfunction, including respiratory efficiency, OXPHOS subunits, and complex amount and assembly. mtDNA depletion and cytochrome c oxidase-negative cells were found ex vivo in biopsies of affected tissues, such as kidney and skeletal muscle. Reduced efficiency of mtDNA replication was also reproduced in vitro, confirming the pathogenic mechanism. Furthermore, ssbp1 suppression in zebrafish induced signs of nephropathy and reduced optic nerve size, the latter phenotype complemented by WT mRNA but not by SSBP1 mutant transcripts. This previously unrecognized disease of mtDNA maintenance implicates SSBP1 mutations as a cause of human pathology.
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Sullivan JA, Stong N, Baugh EH, McDonald MT, Takeuchi A, Shashi V. A pathogenic variant in the SETBP1 hotspot results in a forme-fruste Schinzel-Giedion syndrome. Am J Med Genet A 2020; 182:1947-1951. [PMID: 32445275 DOI: 10.1002/ajmg.a.61630] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/25/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022]
Abstract
Schinzel-Giedion syndrome (SGS; OMIM 269150) is an ultra-rare genetic disorder associated with a distinctive facial gestalt, congenital malformations, severe intellectual disability, and a progressive neurological course. The prognosis for SGS is poor, with survival beyond the first decade rare. Germline, de novo heterozygous variants in the SETBP1 gene cause SGS with the pathogenic variants associated with the SGS phenotype missense and confined to exon 4 of the gene, clustered in a four amino acid (12 bp) hotspot in the SKI homologous region of the SETBP1 protein. We report a patient with a de novo I871S variant within the SKI homologous region, which has been associated with the severe phenotype previously; but our patient has fewer features of SGS and a milder course. This is the first report of a forme-fruste phenotype in a patient with a pathogenic variant within the SGS hotspot on the SETBP1 gene and it highlights the importance of considering atypical clinical presentations in the context of severe ultra-rare genetic disorders.
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Schoch K, Tan QKG, Stong N, Deak KL, McConkie-Rosell A, McDonald MT, Goldstein DB, Jiang YH, Shashi V. Alternative transcripts in variant interpretation: the potential for missed diagnoses and misdiagnoses. Genet Med 2020; 22:1269-1275. [PMID: 32366967 PMCID: PMC7335342 DOI: 10.1038/s41436-020-0781-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/04/2020] [Accepted: 03/10/2020] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Guidelines by professional organizations for assessing variant pathogenicity include the recommendation to utilize biologically relevant transcripts; however, there is variability in transcript selection by laboratories. METHODS We describe three patients whose genomic results were incorrect, because alternative transcripts and tissue expression patterns were not considered by the commercial laboratories. RESULTS In individual 1, a pathogenic coding variant in a brain-expressed isoform of CKDL5 was missed twice on sequencing, because the variant was intronic in the transcripts considered in analysis. In individual 2, a microdeletion affecting KMT2C was not reported on microarray, since deletions of proximal exons in this gene are seen in healthy individuals; however, this individual had a more distal deletion involving the brain-expressed KMT2C isoform, giving her a diagnosis of Kleefstra syndrome. Individual 3 was reported to have a pathogenic variant in exon 10 of OFD1 on exome, but had no typical features of the OFD1-related disorders. Since exon 10 is spliced from the more biologically relevant transcripts of OFD1, it was determined that he did not have an OFD1 disorder. CONCLUSION These examples illustrate the importance of considering alternative transcripts as a potential confounder when genetic results are negative or discordant with the phenotype.
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Mao D, Reuter CM, Ruzhnikov MR, Beck AE, Farrow EG, Emrick LT, Rosenfeld JA, Mackenzie KM, Robak L, Wheeler MT, Burrage LC, Jain M, Liu P, Calame D, Küry S, Sillesen M, Schmitz-Abe K, Tonduti D, Spaccini L, Iascone M, Genetti CA, Koenig MK, Graf M, Tran A, Alejandro M, Lee BH, Thiffault I, Agrawal PB, Bernstein JA, Bellen HJ, Chao HT, Acosta MT, Adam M, Adams DR, Agrawal PB, Alejandro ME, Allard P, Alvey J, Amendola L, Andrews A, Ashley EA, Azamian MS, Bacino CA, Bademci G, Baker E, Balasubramanyam A, Baldridge D, Bale J, Bamshad M, Barbouth D, Batzli GF, Bayrak-Toydemir P, Beck A, Beggs AH, Bejerano G, Bellen HJ, Bennet J, Berg-Rood B, Bernier R, Bernstein JA, Berry GT, Bican A, Bivona S, Blue E, Bohnsack J, Bonnenmann C, Bonner D, Botto L, Briere LC, Brokamp E, Burke EA, Burrage LC, Butte MJ, Byers P, Carey J, Carrasquillo O, Chang TCP, Chanprasert S, Chao HT, Clark GD, Coakley TR, Cobban LA, Cogan JD, Cole FS, Colley HA, Cooper CM, Cope H, Craigen WJ, Cunningham M, D’Souza P, Dai H, Dasari S, Davids M, Dayal JG, Dell’Angelica EC, Dhar SU, Dipple K, Doherty D, Dorrani N, Douine ED, Draper DD, Duncan L, Earl D, Eckstein DJ, Emrick LT, Eng CM, Esteves C, Estwick T, Fernandez L, Ferreira C, Fieg EL, Fisher PG, Fogel BL, Forghani I, Fresard L, Gahl WA, Glass I, Godfrey RA, Golden-Grant K, Goldman AM, Goldstein DB, Grajewski A, Groden CA, Gropman AL, Hahn S, Hamid R, Hanchard NA, Hayes N, High F, Hing A, Hisama FM, Holm IA, Hom J, Horike-Pyne M, Huang A, Huang Y, Isasi R, Jamal F, Jarvik GP, Jarvik J, Jayadev S, Jiang YH, Johnston JM, Karaviti L, Kelley EG, Kiley D, Kohane IS, Kohler JN, Krakow D, Krasnewich DM, Korrick S, Koziura M, Krier JB, Lalani SR, Lam B, Lam C, Lanpher BC, Lanza IR, Lau CC, LeBlanc K, Lee BH, Lee H, Levitt R, Lewis RA, Lincoln SA, Liu P, Liu XZ, Longo N, Loo SK, Loscalzo J, Maas RL, Macnamara EF, MacRae CA, Maduro VV, Majcherska MM, Malicdan MCV, Mamounas LA, Manolio TA, Mao R, Maravilla K, Markello TC, Marom R, Marth G, Martin BA, Martin MG, Martínez-Agosto JA, Marwaha S, McCauley J, McConkie-Rosell A, McCormack CE, McCray AT, Mefford H, Merritt JL, Might M, Mirzaa G, Morava-Kozicz E, Moretti PM, Morimoto M, Mulvihill JJ, Murdock DR, Nath A, Nelson SF, Newman JH, Nicholas SK, Nickerson D, Novacic D, Oglesbee D, Orengo JP, Pace L, Pak S, Pallais JC, Palmer CG, Papp JC, Parker NH, Phillips JA, Posey JE, Postlethwait JH, Potocki L, Pusey BN, Quinlan A, Raskind W, Raja AN, Renteria G, Reuter CM, Rives L, Robertson AK, Rodan LH, Rosenfeld JA, Rowley RK, Ruzhnikov M, Sacco R, Sampson JB, Samson SL, Saporta M, Scott CR, Schaechter J, Schedl T, Schoch K, Scott DA, Shakachite L, Sharma P, Shashi V, Shin J, Signer R, Sillari CH, Silverman EK, Sinsheimer JS, Sisco K, Smith KS, Solnica-Krezel L, Spillmann RC, Stoler JM, Stong N, Sullivan JA, Sun A, Sutton S, Sweetser DA, Sybert V, Tabor HK, Tamburro CP, Tan QKG, Tekin M, Telischi F, Thorson W, Tifft CJ, Toro C, Tran AA, Urv TK, Velinder M, Viskochil D, Vogel TP, Wahl CE, Wallace S, Walley NM, Walsh CA, Walker M, Wambach J, Wan J, Wang LK, Wangler MF, Ward PA, Wegner D, Wener M, Westerfield M, Wheeler MT, Wise AL, Wolfe LA, Woods JD, Yamamoto S, Yang J, Yoon AJ, Yu G, Zastrow DB, Zhao C, Zuchner S. De novo EIF2AK1 and EIF2AK2 Variants Are Associated with Developmental Delay, Leukoencephalopathy, and Neurologic Decompensation. Am J Hum Genet 2020; 106:570-583. [PMID: 32197074 PMCID: PMC7118694 DOI: 10.1016/j.ajhg.2020.02.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 02/28/2020] [Indexed: 02/03/2023] Open
Abstract
EIF2AK1 and EIF2AK2 encode members of the eukaryotic translation initiation factor 2 alpha kinase (EIF2AK) family that inhibits protein synthesis in response to physiologic stress conditions. EIF2AK2 is also involved in innate immune response and the regulation of signal transduction, apoptosis, cell proliferation, and differentiation. Despite these findings, human disorders associated with deleterious variants in EIF2AK1 and EIF2AK2 have not been reported. Here, we describe the identification of nine unrelated individuals with heterozygous de novo missense variants in EIF2AK1 (1/9) or EIF2AK2 (8/9). Features seen in these nine individuals include white matter alterations (9/9), developmental delay (9/9), impaired language (9/9), cognitive impairment (8/9), ataxia (6/9), dysarthria in probands with verbal ability (6/9), hypotonia (7/9), hypertonia (6/9), and involuntary movements (3/9). Individuals with EIF2AK2 variants also exhibit neurological regression in the setting of febrile illness or infection. We use mammalian cell lines and proband-derived fibroblasts to further confirm the pathogenicity of variants in these genes and found reduced kinase activity. EIF2AKs phosphorylate eukaryotic translation initiation factor 2 subunit 1 (EIF2S1, also known as EIF2α), which then inhibits EIF2B activity. Deleterious variants in genes encoding EIF2B proteins cause childhood ataxia with central nervous system hypomyelination/vanishing white matter (CACH/VWM), a leukodystrophy characterized by neurologic regression in the setting of febrile illness and other stressors. Our findings indicate that EIF2AK2 missense variants cause a neurodevelopmental syndrome that may share phenotypic and pathogenic mechanisms with CACH/VWM.
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Baldridge D, Spillmann RC, Wegner DJ, Wambach JA, White FV, Sisco K, Toler TL, Dickson PI, Cole FS, Shashi V, Grange DK. Phenotypic expansion of KMT2D-related disorder: Beyond Kabuki syndrome. Am J Med Genet A 2020; 182:1053-1065. [PMID: 32083401 DOI: 10.1002/ajmg.a.61518] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 12/13/2022]
Abstract
Pathogenic variants in KMT2D, which encodes lysine specific methyltransferase 2D, cause autosomal dominant Kabuki syndrome, associated with distinctive dysmorphic features including arched eyebrows, long palpebral fissures with eversion of the lower lid, large protuberant ears, and fetal finger pads. Most disease-causing variants identified to date are putative loss-of-function alleles, although 15-20% of cases are attributed to missense variants. We describe here four patients (including one previously published patient) with de novo KMT2D missense variants and with shared but unusual clinical findings not typically seen in Kabuki syndrome, including athelia (absent nipples), choanal atresia, hypoparathyroidism, delayed or absent pubertal development, and extreme short stature. These individuals also lack the typical dysmorphic facial features found in Kabuki syndrome. Two of the four patients had severe interstitial lung disease. All of these variants cluster within a 40-amino-acid region of the protein that is located just N-terminal of an annotated coiled coil domain. These findings significantly expand the phenotypic spectrum of features associated with variants in KMT2D beyond those seen in Kabuki syndrome and suggest a possible new underlying disease mechanism for these patients.
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Baloh C, Markert ML, Shashi V, Sleasman J. Predicting Autoimmunity Development in 22q11.2DS. J Allergy Clin Immunol 2020. [DOI: 10.1016/j.jaci.2019.12.679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Johnson BV, Kumar R, Oishi S, Alexander S, Kasherman M, Vega MS, Ivancevic A, Gardner A, Domingo D, Corbett M, Parnell E, Yoon S, Oh T, Lines M, Lefroy H, Kini U, Van Allen M, Grønborg S, Mercier S, Küry S, Bézieau S, Pasquier L, Raynaud M, Afenjar A, Billette de Villemeur T, Keren B, Désir J, Van Maldergem L, Marangoni M, Dikow N, Koolen DA, VanHasselt PM, Weiss M, Zwijnenburg P, Sa J, Reis CF, López-Otín C, Santiago-Fernández O, Fernández-Jaén A, Rauch A, Steindl K, Joset P, Goldstein A, Madan-Khetarpal S, Infante E, Zackai E, Mcdougall C, Narayanan V, Ramsey K, Mercimek-Andrews S, Pena L, Shashi V, Schoch K, Sullivan JA, Pinto E Vairo F, Pichurin PN, Ewing SA, Barnett SS, Klee EW, Perry MS, Koenig MK, Keegan CE, Schuette JL, Asher S, Perilla-Young Y, Smith LD, Rosenfeld JA, Bhoj E, Kaplan P, Li D, Oegema R, van Binsbergen E, van der Zwaag B, Smeland MF, Cutcutache I, Page M, Armstrong M, Lin AE, Steeves MA, Hollander ND, Hoffer MJV, Reijnders MRF, Demirdas S, Koboldt DC, Bartholomew D, Mosher TM, Hickey SE, Shieh C, Sanchez-Lara PA, Graham JM, Tezcan K, Schaefer GB, Danylchuk NR, Asamoah A, Jackson KE, Yachelevich N, Au M, Pérez-Jurado LA, Kleefstra T, Penzes P, Wood SA, Burne T, Pierson TM, Piper M, Gécz J, Jolly LA. Partial Loss of USP9X Function Leads to a Male Neurodevelopmental and Behavioral Disorder Converging on Transforming Growth Factor β Signaling. Biol Psychiatry 2020; 87:100-112. [PMID: 31443933 PMCID: PMC6925349 DOI: 10.1016/j.biopsych.2019.05.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/23/2019] [Accepted: 05/30/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND The X-chromosome gene USP9X encodes a deubiquitylating enzyme that has been associated with neurodevelopmental disorders primarily in female subjects. USP9X escapes X inactivation, and in female subjects de novo heterozygous copy number loss or truncating mutations cause haploinsufficiency culminating in a recognizable syndrome with intellectual disability and signature brain and congenital abnormalities. In contrast, the involvement of USP9X in male neurodevelopmental disorders remains tentative. METHODS We used clinically recommended guidelines to collect and interrogate the pathogenicity of 44 USP9X variants associated with neurodevelopmental disorders in males. Functional studies in patient-derived cell lines and mice were used to determine mechanisms of pathology. RESULTS Twelve missense variants showed strong evidence of pathogenicity. We define a characteristic phenotype of the central nervous system (white matter disturbances, thin corpus callosum, and widened ventricles); global delay with significant alteration of speech, language, and behavior; hypotonia; joint hypermobility; visual system defects; and other common congenital and dysmorphic features. Comparison of in silico and phenotypical features align additional variants of unknown significance with likely pathogenicity. In support of partial loss-of-function mechanisms, using patient-derived cell lines, we show loss of only specific USP9X substrates that regulate neurodevelopmental signaling pathways and a united defect in transforming growth factor β signaling. In addition, we find correlates of the male phenotype in Usp9x brain-specific knockout mice, and further resolve loss of hippocampal-dependent learning and memory. CONCLUSIONS Our data demonstrate the involvement of USP9X variants in a distinctive neurodevelopmental and behavioral syndrome in male subjects and identify plausible mechanisms of pathogenesis centered on disrupted transforming growth factor β signaling and hippocampal function.
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