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1.
Am J Hum Genet ; 110(8): 1356-1376, 2023 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-37421948

RESUMO

By converting physical forces into electrical signals or triggering intracellular cascades, stretch-activated ion channels allow the cell to respond to osmotic and mechanical stress. Knowledge of the pathophysiological mechanisms underlying associations of stretch-activated ion channels with human disease is limited. Here, we describe 17 unrelated individuals with severe early-onset developmental and epileptic encephalopathy (DEE), intellectual disability, and severe motor and cortical visual impairment associated with progressive neurodegenerative brain changes carrying ten distinct heterozygous variants of TMEM63B, encoding for a highly conserved stretch-activated ion channel. The variants occurred de novo in 16/17 individuals for whom parental DNA was available and either missense, including the recurrent p.Val44Met in 7/17 individuals, or in-frame, all affecting conserved residues located in transmembrane regions of the protein. In 12 individuals, hematological abnormalities co-occurred, such as macrocytosis and hemolysis, requiring blood transfusions in some. We modeled six variants (p.Val44Met, p.Arg433His, p.Thr481Asn, p.Gly580Ser, p.Arg660Thr, and p.Phe697Leu), each affecting a distinct transmembrane domain of the channel, in transfected Neuro2a cells and demonstrated inward leak cation currents across the mutated channel even in isotonic conditions, while the response to hypo-osmotic challenge was impaired, as were the Ca2+ transients generated under hypo-osmotic stimulation. Ectopic expression of the p.Val44Met and p.Gly580Cys variants in Drosophila resulted in early death. TMEM63B-associated DEE represents a recognizable clinicopathological entity in which altered cation conductivity results in a severe neurological phenotype with progressive brain damage and early-onset epilepsy associated with hematological abnormalities in most individuals.


Assuntos
Encefalopatias , Deficiência Intelectual , Humanos , Encefalopatias/genética , Canais Iônicos/genética , Encéfalo , Deficiência Intelectual/genética , Fenótipo
2.
Hum Mol Genet ; 32(3): 386-401, 2023 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-35981081

RESUMO

De novo deleterious and heritable biallelic mutations in the DNA binding domain (DBD) of the transcription factor deformed epidermal autoregulatory factor 1 (DEAF1) result in a phenotypic spectrum of disorders termed DEAF1-associated neurodevelopmental disorders (DAND). RNA-sequencing using hippocampal RNA from mice with conditional deletion of Deaf1 in the central nervous system indicate that loss of Deaf1 activity results in the altered expression of genes involved in neuronal function, dendritic spine maintenance, development, and activity, with reduced dendritic spines in hippocampal regions. Since DEAF1 is not a dosage-sensitive gene, we assessed the dominant negative activity of previously identified de novo variants and a heritable recessive DEAF1 variant on selected DEAF1-regulated genes in 2 different cell models. While no altered gene expression was observed in cells over-expressing the recessive heritable variant, the gene expression profiles of cells over-expressing de novo variants resulted in similar gene expression changes as observed in CRISPR-Cas9-mediated DEAF1-deleted cells. Altered expression of DEAF1-regulated genes was rescued by exogenous expression of WT-DEAF1 but not by de novo variants in cells lacking endogenous DEAF1. De novo heterozygous variants within the DBD of DEAF1 were identified in 10 individuals with a phenotypic spectrum including autism spectrum disorder, developmental delays, sleep disturbance, high pain tolerance, and mild dysmorphic features. Functional assays demonstrate these variants alter DEAF1 transcriptional activity. Taken together, this study expands the clinical phenotypic spectrum of individuals with DAND, furthers our understanding of potential roles of DEAF1 on neuronal function, and demonstrates dominant negative activity of identified de novo variants.


Assuntos
Transtorno do Espectro Autista , Transtornos do Neurodesenvolvimento , Animais , Camundongos , Proteínas de Ligação a DNA/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transtornos do Neurodesenvolvimento/genética , RNA
3.
Am J Hum Genet ; 109(4): 750-758, 2022 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-35202563

RESUMO

Chromatin is essentially an array of nucleosomes, each of which consists of the DNA double-stranded fiber wrapped around a histone octamer. This organization supports cellular processes such as DNA replication, DNA transcription, and DNA repair in all eukaryotes. Human histone H4 is encoded by fourteen canonical histone H4 genes, all differing at the nucleotide level but encoding an invariant protein. Here, we present a cohort of 29 subjects with de novo missense variants in six H4 genes (H4C3, H4C4, H4C5, H4C6, H4C9, and H4C11) identified by whole-exome sequencing and matchmaking. All individuals present with neurodevelopmental features of intellectual disability and motor and/or gross developmental delay, while non-neurological features are more variable. Ten amino acids are affected, six recurrently, and are all located within the H4 core or C-terminal tail. These variants cluster to specific regions of the core H4 globular domain, where protein-protein interactions occur with either other histone subunits or histone chaperones. Functional consequences of the identified variants were evaluated in zebrafish embryos, which displayed abnormal general development, defective head organs, and reduced body axis length, providing compelling evidence for the causality of the reported disorder(s). While multiple developmental syndromes have been linked to chromatin-associated factors, missense-bearing histone variants (e.g., H3 oncohistones) are only recently emerging as a major cause of pathogenicity. Our findings establish a broader involvement of H4 variants in developmental syndromes.


Assuntos
Histonas , Peixe-Zebra , Animais , Cromatina , DNA , Histonas/metabolismo , Humanos , Síndrome , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
4.
Am J Hum Genet ; 108(6): 1138-1150, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-33909992

RESUMO

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


Assuntos
Anormalidades Craniofaciais/etiologia , Heterozigoto , Deficiência Intelectual/etiologia , Transtornos do Desenvolvimento da Linguagem/etiologia , Mutação com Perda de Função , Proteínas de Ligação a RNA/genética , Adolescente , Adulto , Criança , Pré-Escolar , Anormalidades Craniofaciais/patologia , Feminino , Haploinsuficiência , Humanos , Lactente , Deficiência Intelectual/patologia , Transtornos do Desenvolvimento da Linguagem/patologia , Masculino , Linhagem , Fenótipo , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Síndrome , Adulto Jovem
5.
Eur J Pediatr ; 183(1): 345-355, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37889289

RESUMO

This study aims to inform future genetic reanalysis management by evaluating the yield of whole-exome sequencing (WES) reanalysis in standard patient care in the Netherlands. Single-center data of 159 patients with a neurodevelopmental disorder (NDD), in which WES analysis and reanalysis were performed between January 1, 2014, and December 31, 2021, was retrospectively collected. Patients were included if they were under the age of 18 years at initial analysis and if this initial analysis did not result in a diagnosis. Demographic, phenotypic, and genotypic characteristics of patients were collected and analyzed. The primary outcomes of our study were (i) diagnostic yield at reanalysis, (ii) reasons for detecting a new possibly causal variant at reanalysis, (iii) unsolicited findings, and (iv) factors associated with positive result of reanalysis. In addition, we conducted a questionnaire study amongst the 7 genetic department in the Netherlands creating an overview of used techniques, yield, and organization of WES reanalysis. The single-center data show that in most cases, WES reanalysis was initiated by the clinical geneticist (65%) or treating physician (30%). The mean time between initial WES analysis and reanalysis was 3.7 years. A new (likely) pathogenic variant or VUS with a clear link to the phenotype was found in 20 initially negative cases, resulting in a diagnostic yield of 12.6%. In 75% of these patients, the diagnosis had clinical consequences, as for example, a screening plan for associated signs and symptoms could be devised. Most (32%) of the (likely) causal variants identified at WES reanalysis were discovered due to a newly described gene-disease association. In addition to the 12.6% diagnostic yield based on new diagnoses, reclassification of a variant of uncertain significance found at initial analysis led to a definite diagnosis in three patients. Diagnostic yield was higher in patients with dysmorphic features compared to patients without clear dysmorphic features (yield 27% vs. 6%; p = 0.001). CONCLUSIONS: Our results show that WES reanalysis in patients with NDD in standard patient care leads to a substantial increase in genetic diagnoses. In the majority of newly diagnosed patients, the diagnosis had clinical consequences. Knowledge about the clinical impact of WES reanalysis, clinical characteristics associated with higher yield, and the yield per year after a negative WES in larger clinical cohorts is warranted to inform guidelines for genetic reanalysis. These guidelines will be of great value for pediatricians, pediatric rehabilitation specialists, and pediatric neurologists in daily care of patients with NDD. WHAT IS KNOWN: • Whole exome sequencing can cost-effectively identify a genetic cause of intellectual disability in about 30-40% of patients. • WES reanalysis in a research setting can lead to a definitive diagnosis in 10-20% of previously exome negative cases. WHAT IS NEW: • WES reanalysis in standard patient care resulted in a diagnostic yield of 13% in previously exome negative children with NDD. • The presence of dysmorphic features is associated with an increased diagnostic yield of WES reanalysis.


Assuntos
Exoma , Deficiência Intelectual , Criança , Humanos , Adolescente , Sequenciamento do Exoma , Estudos Retrospectivos , Fenótipo , Exoma/genética , Deficiência Intelectual/diagnóstico , Testes Genéticos/métodos
6.
Genet Med ; 25(1): 135-142, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36399134

RESUMO

PURPOSE: Protein arginine methyltransferase 7 (PRMT7) is a member of a family of enzymes that catalyzes the methylation of arginine residues on several protein substrates. Biallelic pathogenic PRMT7 variants have previously been associated with a syndromic neurodevelopmental disorder characterized by short stature, brachydactyly, intellectual developmental disability, and seizures. To our knowledge, no comprehensive study describes the detailed clinical characteristics of this syndrome. Thus, we aim to delineate the phenotypic spectrum of PRMT7-related disorder. METHODS: We assembled a cohort of 51 affected individuals from 39 different families, gathering clinical information from 36 newly described affected individuals and reviewing data of 15 individuals from the literature. RESULTS: The main clinical characteristics of the PRMT7-related syndrome are short stature, mild to severe developmental delay/intellectual disability, hypotonia, brachydactyly, and distinct facial morphology, including bifrontal narrowing, prominent supraorbital ridges, sparse eyebrows, short nose with full/broad nasal tip, thin upper lip, full and everted lower lip, and a prominent or squared-off jaw. Additional variable findings include seizures, obesity, nonspecific magnetic resonance imaging abnormalities, eye abnormalities (i.e., strabismus or nystagmus), and hearing loss. CONCLUSION: This study further delineates and expands the molecular, phenotypic spectrum and natural history of PRMT7-related syndrome characterized by a neurodevelopmental disorder with skeletal, growth, and endocrine abnormalities.


Assuntos
Braquidactilia , Nanismo , Deficiência Intelectual , Anormalidades Musculoesqueléticas , Transtornos do Neurodesenvolvimento , Humanos , Transtornos do Neurodesenvolvimento/genética , Deficiência Intelectual/genética , Nanismo/genética , Obesidade/genética , Fenótipo , Proteína-Arginina N-Metiltransferases/genética
7.
J Genet Couns ; 32(1): 153-165, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36056622

RESUMO

Couples at risk of transmitting a genetic disease to their offspring may experience doubts about their reproductive options. This study examines the effects of an online decision aid (DA) on the (joint) reproductive decision-making process of couples (not pregnant at time of inclusion) at risk of transmitting a genetic disease to their offspring. The primary outcome is decisional conflict, and secondary outcomes are knowledge, realistic expectations, deliberation, joint informed decision-making, and decisional self-efficacy. These outcomes were measured with a pretest-posttest design: before use (T0), after use (T1), and 2 weeks after use (T2) of the decision aid (DA). Usability of the DA was assessed at T1. Paired sample t-tests were used to compute differences between baseline and subsequent measurements. The comparisons of T0-T1 and T0-T2 indicate a significant reduction in mean decisional conflict scores with stronger effects for participants with high baseline decisional conflict scores. Furthermore, use of the DA led to increased knowledge, improved realistic expectations, and increased levels of deliberation, with higher increase in participants with low baseline scores. Decision self-efficacy only improved for participants with lower baseline scores. Participants indicated that the information in the DA was comprehensible and clearly organized. These first results indicate that this online DA is an appropriate tool to support couples at risk of transmitting a genetic disease and a desire to have (a) child(ren) in their reproductive decision-making process.


Assuntos
Tomada de Decisões , Técnicas de Apoio para a Decisão , Criança , Humanos , Gravidez , Feminino , Projetos Piloto , Reprodução , Emoções
8.
Am J Med Genet C Semin Med Genet ; 190(1): 102-108, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35488810

RESUMO

Biallelic loss-of-function (LoF) variants in CENPF gene are responsible for Strømme syndrome, a condition presenting with intestinal atresia, anterior ocular chamber anomalies, and microcephaly. Through an international collaboration, four individuals (three males and one female) carrying CENPF biallelic variants, including two missense variants in homozygous state and four LoF variants, were identified by exome sequencing. All individuals had variable degree of developmental delay/intellectual disability and microcephaly (ranging from -2.9 SDS to -5.6 SDS) and a recognizable pattern of dysmorphic facial features including inverted-V shaped interrupted eyebrows, epicanthal fold, depressed nasal bridge, and pointed chin. Although one of the cases had duodenal atresia, all four individuals did not have the combination of internal organ malformations of Strømme syndrome (intestinal atresia and anterior eye segment abnormalities). Immunofluorescence analysis on skin fibroblasts on one of the four cases with the antibody for ARL13B that decorates primary cilia revealed shorter primary cilia that are consistent with a ciliary defect. This case-series of individuals with biallelic CENPF variants suggests the spectrum of clinical manifestations of the disorder that may be related to CENPF variants is broad and can include phenotypes lacking the cardinal features of Strømme syndrome.


Assuntos
Proteínas Cromossômicas não Histona , Deficiência Intelectual , Atresia Intestinal , Microcefalia , Proteínas dos Microfilamentos , Proteínas Cromossômicas não Histona/genética , Anormalidades do Olho , Feminino , Humanos , Atresia Intestinal/genética , Masculino , Microcefalia/genética , Proteínas dos Microfilamentos/genética , Mutação/genética , Fenótipo
9.
Hum Mol Genet ; 29(9): 1426-1439, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32202298

RESUMO

Defects in the mRNA export scaffold protein GANP, encoded by the MCM3AP gene, cause autosomal recessive early-onset peripheral neuropathy with or without intellectual disability. We extend here the phenotypic range associated with MCM3AP variants, by describing a severely hypotonic child and a sibling pair with a progressive encephalopathic syndrome. In addition, our analysis of skin fibroblasts from affected individuals from seven unrelated families indicates that disease variants result in depletion of GANP except when they alter critical residues in the Sac3 mRNA binding domain. GANP depletion was associated with more severe phenotypes compared with the Sac3 variants. Patient fibroblasts showed transcriptome alterations that suggested intron content-dependent regulation of gene expression. For example, all differentially expressed intronless genes were downregulated, including ATXN7L3B, which couples mRNA export to transcription activation by association with the TREX-2 and SAGA complexes. Our results provide insight into the molecular basis behind genotype-phenotype correlations in MCM3AP-associated disease and suggest mechanisms by which GANP defects might alter RNA metabolism.


Assuntos
Acetiltransferases/genética , Flavoproteínas/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Doenças do Sistema Nervoso/genética , Proteínas Nucleares/genética , Monoéster Fosfórico Hidrolases/genética , Fatores de Transcrição/genética , Acetiltransferases/química , Acetiltransferases/ultraestrutura , Idade de Início , Antígenos de Superfície/genética , Núcleo Celular/genética , Criança , Pré-Escolar , Exodesoxirribonucleases/genética , Feminino , Regulação da Expressão Gênica/genética , Glicoproteínas/genética , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Peptídeos e Proteínas de Sinalização Intracelular/química , Íntrons/genética , Masculino , Doenças do Sistema Nervoso/patologia , Proteínas Nucleares/ultraestrutura , Doenças do Sistema Nervoso Periférico/genética , Doenças do Sistema Nervoso Periférico/patologia , Fenótipo , Fosfoproteínas/genética , Conformação Proteica , Transporte de RNA/genética , RNA Mensageiro/genética
10.
Am J Hum Genet ; 104(6): 1116-1126, 2019 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-31104771

RESUMO

Huntington disease (HD) is caused by a CAG repeat expansion in the huntingtin (HTT) gene. Although the length of this repeat is inversely correlated with age of onset (AOO), it does not fully explain the variability in AOO. We assessed the sequence downstream of the CAG repeat in HTT [reference: (CAG)n-CAA-CAG], since variants within this region have been previously described, but no study of AOO has been performed. These analyses identified a variant that results in complete loss of interrupting (LOI) adenine nucleotides in this region [(CAG)n-CAG-CAG]. Analysis of multiple HD pedigrees showed that this LOI variant is associated with dramatically earlier AOO (average of 25 years) despite the same polyglutamine length as in individuals with the interrupting penultimate CAA codon. This LOI allele is particularly frequent in persons with reduced penetrance alleles who manifest with HD and increases the likelihood of presenting clinically with HD with a CAG of 36-39 repeats. Further, we show that the LOI variant is associated with increased somatic repeat instability, highlighting this as a significant driver of this effect. These findings indicate that the number of uninterrupted CAG repeats, which is lengthened by the LOI, is the most significant contributor to AOO of HD and is more significant than polyglutamine length, which is not altered in these individuals. In addition, we identified another variant in this region, where the CAA-CAG sequence is duplicated, which was associated with later AOO. Identification of these cis-acting modifiers have potentially important implications for genetic counselling in HD-affected families.


Assuntos
Códon/genética , Doença de Huntington/genética , Doença de Huntington/patologia , Peptídeos/genética , Expansão das Repetições de Trinucleotídeos/genética , Adolescente , Adulto , Idade de Início , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem
11.
Am J Hum Genet ; 105(3): 493-508, 2019 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-31447100

RESUMO

Histones mediate dynamic packaging of nuclear DNA in chromatin, a process that is precisely controlled to guarantee efficient compaction of the genome and proper chromosomal segregation during cell division and to accomplish DNA replication, transcription, and repair. Due to the important structural and regulatory roles played by histones, it is not surprising that histone functional dysregulation or aberrant levels of histones can have severe consequences for multiple cellular processes and ultimately might affect development or contribute to cell transformation. Recently, germline frameshift mutations involving the C-terminal tail of HIST1H1E, which is a widely expressed member of the linker histone family and facilitates higher-order chromatin folding, have been causally linked to an as-yet poorly defined syndrome that includes intellectual disability. We report that these mutations result in stable proteins that reside in the nucleus, bind to chromatin, disrupt proper compaction of DNA, and are associated with a specific methylation pattern. Cells expressing these mutant proteins have a dramatically reduced proliferation rate and competence, hardly enter into the S phase, and undergo accelerated senescence. Remarkably, clinical assessment of a relatively large cohort of subjects sharing these mutations revealed a premature aging phenotype as a previously unrecognized feature of the disorder. Our findings identify a direct link between aberrant chromatin remodeling, cellular senescence, and accelerated aging.


Assuntos
Senescência Celular/fisiologia , Histonas/fisiologia , Aneuploidia , Nucléolo Celular/metabolismo , Criança , Cromatina/metabolismo , Metilação de DNA , Feminino , Histonas/química , Humanos , Lactente , Masculino , Pessoa de Meia-Idade
12.
Clin Genet ; 101(1): 65-77, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34611884

RESUMO

Prenatal exome sequencing (pES) is a promising tool for diagnosing genetic disorders when structural anomalies are detected on prenatal ultrasound. The aim of this study was to investigate the diagnostic yield and clinical impact of pES as an additional modality for fetal neurologists who counsel parents in case of congenital anomalies of the central nervous system (CNS). We assessed 20 pregnancies of 19 couples who were consecutively referred to the fetal neurologist for CNS anomalies. pES had a diagnostic yield of 53% (10/19) with most diagnosed pregnancies having agenesis or hypoplasia of the corpus callosum (7/10). Overall clinical impact was 63% (12/19), of which the pES result aided parental decision making in 55% of cases (6/11), guided perinatal management in 75% of cases (3/4), and was helpful in approving a late termination of pregnancy request in 75% of cases (3/4). Our data suggest that pES had a high diagnostic yield when CNS anomalies are present, although this study is limited by its small sample size. Moreover, pES had substantial clinical impact, which warrants implementation of pES in the routine care of the fetal neurologist in close collaboration with gynecologists and clinical geneticists.


Assuntos
Sequenciamento do Exoma , Feto/anormalidades , Malformações do Sistema Nervoso/diagnóstico , Malformações do Sistema Nervoso/genética , Diagnóstico Pré-Natal/métodos , Tomada de Decisão Clínica , Consanguinidade , Gerenciamento Clínico , Feminino , Feto/diagnóstico por imagem , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Malformações do Sistema Nervoso/terapia , Neurologistas , Gravidez , Resultado da Gravidez , Ultrassonografia Pré-Natal , Sequenciamento do Exoma/métodos
13.
Am J Med Genet A ; 188(3): 867-877, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34894057

RESUMO

SCN2A-related disorders include intellectual disability, autism spectrum disorder, seizures, episodic ataxia, and schizophrenia. In this study, the phenotype-genotype association in SCN2A-related disorders was further delineated by collecting detailed clinical and molecular characteristics. Using previously proposed genotype-phenotype hypotheses based on variant function and position, the potential of phenotype prediction from the variants found was examined. Patients were identified through the Deciphering Developmental Disorders study and gene matching strategies. Phenotypic information and variant interpretation evidence were collated. Seventeen previously unreported patients and five patients who had been previously reported (but with minimal phenotypic and segregation data) were included (10 males, 12 females; median age 10.5 years). All patients had developmental delays and the majority had intellectual disabilities. Seizures were reported in 15 of 22 (68.2%), four of 22 (18.2%) had autism spectrum disorder and no patients were reported with episodic ataxia. The majority of variants were de novo. One family had presumed gonadal mosaicism. The correlation of the use of sodium channel-blocking antiepileptic drugs with phenotype or genotype was variable. These data suggest that variant type and position alone can provide some predictive information about the phenotype in a proportion of cases, but more precise assessment of variant function is needed for meaningful phenotype prediction.


Assuntos
Transtorno do Espectro Autista , Deficiência Intelectual , Transtorno do Espectro Autista/genética , Criança , Feminino , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Masculino , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Fenótipo , Convulsões/genética
15.
Neurogenetics ; 22(4): 263-269, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34218362

RESUMO

ANK3 encodes multiple isoforms of ankyrin-G, resulting in variegated tissue expression and function, especially regarding its role in neuronal development. Based on the zygosity, location, and type, ANK3 variants result in different neurodevelopmental phenotypes. Autism spectrum disorder has been associated with heterozygous missense variants in ANK3, whereas a more severe neurodevelopmental phenotype is caused by isoform-dependent, autosomal-dominant, or autosomal-recessive loss-of-function variants. Here, we present four individuals affected by a variable neurodevelopmental phenotype harboring a heterozygous frameshift or nonsense variant affecting all ANK3 transcripts. Thus, we provide further evidence of an isoform-based phenotypic continuum underlying ANK3-associated pathologies and expand its phenotypic spectrum.


Assuntos
Anquirinas/genética , Transtorno do Espectro Autista/genética , Deficiência Intelectual/genética , Transtornos do Neurodesenvolvimento/genética , Adolescente , Criança , Humanos , Perda de Heterozigosidade , Masculino , Mutação de Sentido Incorreto/genética , Fenótipo , Isoformas de Proteínas/genética
16.
Am J Hum Genet ; 102(5): 995-1007, 2018 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-29656858

RESUMO

Developmental and epileptic encephalopathies (DEEs) represent a large clinical and genetic heterogeneous group of neurodevelopmental diseases. The identification of pathogenic genetic variants in DEEs remains crucial for deciphering this complex group and for accurately caring for affected individuals (clinical diagnosis, genetic counseling, impacting medical, precision therapy, clinical trials, etc.). Whole-exome sequencing and intensive data sharing identified a recurrent de novo PACS2 heterozygous missense variant in 14 unrelated individuals. Their phenotype was characterized by epilepsy, global developmental delay with or without autism, common cerebellar dysgenesis, and facial dysmorphism. Mixed focal and generalized epilepsy occurred in the neonatal period, controlled with difficulty in the first year, but many improved in early childhood. PACS2 is an important PACS1 paralog and encodes a multifunctional sorting protein involved in nuclear gene expression and pathway traffic regulation. Both proteins harbor cargo(furin)-binding regions (FBRs) that bind cargo proteins, sorting adaptors, and cellular kinase. Compared to the defined PACS1 recurrent variant series, individuals with PACS2 variant have more consistently neonatal/early-infantile-onset epilepsy that can be challenging to control. Cerebellar abnormalities may be similar but PACS2 individuals exhibit a pattern of clear dysgenesis ranging from mild to severe. Functional studies demonstrated that the PACS2 recurrent variant reduces the ability of the predicted autoregulatory domain to modulate the interaction between the PACS2 FBR and client proteins, which may disturb cellular function. These findings support the causality of this recurrent de novo PACS2 heterozygous missense in DEEs with facial dysmorphim and cerebellar dysgenesis.


Assuntos
Doenças Cerebelares/genética , Epilepsia Generalizada/genética , Fácies , Mutação de Sentido Incorreto/genética , Proteínas de Transporte Vesicular/genética , Idade de Início , Pré-Escolar , Feminino , Heterozigoto , Humanos , Lactente , Recém-Nascido , Masculino , Fenótipo
17.
Genet Med ; 22(12): 2108-2113, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32741964

RESUMO

PURPOSE: In some Huntington disease (HD) patients, the "loss of interruption" (LOI) variant eliminates an interrupting codon in the HTT CAG-repeat tract, which causes earlier age of onset (AOO). The magnitude of this effect is uncertain, since previous studies included few LOI carriers, and the variant also causes CAG size misestimation. We developed a rapid LOI detection screen, enabling unbiased frequency estimation among manifest HD patients. Additionally, we combined published data with clinical data from newly identified patients to accurately characterize the LOI's effect on AOO. METHODS: We developed a LOI detection polymerase chain reaction (PCR) assay, and screened patients to estimate the frequency of the LOI variant and its effect on AOO. RESULTS: Mean onset for LOI carriers (n = 49) is 20.4 years earlier than expected based on diagnosed CAG size. After correcting for CAG size underestimation, the variant is still associated with onset 9.5 years earlier. The LOI is present in 1.02% of symptomatic HD patients, and in 32.2% of symptomatic reduced penetrance (RP) range patients (36-39 CAGs). CONCLUSION: The LOI causes significantly earlier onset, greater than expected by CAG length, particularly in persons with 36-39 CAG repeats. Detection of this variant has implications for HD families, especially for those in the RP range.


Assuntos
Doença de Huntington , Códon , Heterozigoto , Humanos , Proteína Huntingtina/genética , Doença de Huntington/diagnóstico , Doença de Huntington/epidemiologia , Doença de Huntington/genética , Penetrância , Repetições de Trinucleotídeos/genética
18.
Genet Med ; 22(4): 797-802, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31776469

RESUMO

PURPOSE: To delineate the genotype-phenotype correlation in individuals with likely pathogenic variants in the CLTC gene. METHODS: We describe 13 individuals with de novo CLTC variants. Causality of variants was determined by using the tolerance landscape of CLTC and computer-assisted molecular modeling where applicable. Phenotypic abnormalities observed in the individuals identified with missense and in-frame variants were compared with those with nonsense or frameshift variants in CLTC. RESULTS: All de novo variants were judged to be causal. Combining our data with that of 14 previously reported affected individuals (n = 27), all had intellectual disability (ID), ranging from mild to moderate/severe, with or without additional neurologic, behavioral, craniofacial, ophthalmologic, and gastrointestinal features. Microcephaly, hypoplasia of the corpus callosum, and epilepsy were more frequently observed in individuals with missense and in-frame variants than in those with nonsense and frameshift variants. However, this difference was not significant. CONCLUSIONS: The wide phenotypic variability associated with likely pathogenic CLTC variants seems to be associated with allelic heterogeneity. The detailed clinical characterization of a larger cohort of individuals with pathogenic CLTC variants is warranted to support the hypothesis that missense and in-frame variants exert a dominant-negative effect, whereas the nonsense and frameshift variants would result in haploinsufficiency.


Assuntos
Epilepsia , Deficiência Intelectual , Microcefalia , Variação Biológica da População , Corpo Caloso , Epilepsia/genética , Humanos , Deficiência Intelectual/genética , Microcefalia/genética , Fenótipo
19.
Genet Med ; 21(5): 1074-1082, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30287924

RESUMO

PURPOSE: Several studies have reported diagnostic yields up to 57% for rapid exome or genome sequencing (rES/GS) as a single test in neonatal intensive care unit (NICU) patients, but the additional yield of rES/GS compared with other available diagnostic options still remains unquantified in this population. METHODS: We retrospectively evaluated all genetic NICU consultations in a 2-year period. RESULTS: In 132 retrospectively evaluated NICU consultations 27 of 32 diagnoses (84.4%) were made using standard genetic workup. Most diagnoses (65.6%) were made within 16 days. Diagnostic ES yield was 5/29 (17.2%). Genetic diagnoses had a direct effect on clinical management in 90.6% (29/32) of patients. CONCLUSIONS: Our study shows that exome sequencing has a place in NICU diagnostics, but given the associated costs and the high yield of alternative diagnostic strategies, we recommend to first perform clinical genetic consultation.


Assuntos
Doenças do Recém-Nascido/diagnóstico , Doenças do Recém-Nascido/genética , Mapeamento Cromossômico/métodos , Exoma/genética , Feminino , Testes Genéticos/economia , Estudo de Associação Genômica Ampla/métodos , Humanos , Recém-Nascido , Terapia Intensiva Neonatal , Masculino , Estudos Retrospectivos , Sequenciamento do Exoma/economia , Sequenciamento do Exoma/métodos
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