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1.
Genet Med ; 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31316167

RESUMO

PURPOSE: Congenital contractural arachnodactyly (CCA) is an autosomal dominant connective tissue disorder manifesting joint contractures, arachnodactyly, crumpled ears, and kyphoscoliosis as main features. Due to its rarity, rather aspecific clinical presentation, and overlap with other conditions including Marfan syndrome, the diagnosis is challenging, but important for prognosis and clinical management. CCA is caused by pathogenic variants in FBN2, encoding fibrillin-2, but locus heterogeneity has been suggested. We designed a clinical scoring system and diagnostic criteria to support the diagnostic process and guide molecular genetic testing. METHODS: In this retrospective study, we assessed 167 probands referred for FBN2 analysis and classified them into a FBN2-positive (n = 44) and FBN2-negative group (n = 123) following molecular analysis. We developed a 20-point weighted clinical scoring system based on the prevalence of ten main clinical characteristics of CCA in both groups. RESULTS: The total score was significantly different between the groups (P < 0.001) and was indicative for classifying patients into unlikely CCA (total score <7) and likely CCA (total score ≥7) groups. CONCLUSIONS: Our clinical score is helpful for clinical guidance for patients suspected to have CCA, and provides a quantitative tool for phenotyping in research settings.

2.
Genome Res ; 29(7): 1057-1066, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31160375

RESUMO

Germline mutations in fundamental epigenetic regulatory molecules including DNA methyltransferase 3 alpha (DNMT3A) are commonly associated with growth disorders, whereas somatic mutations are often associated with malignancy. We profiled genome-wide DNA methylation patterns in DNMT3A c.2312G > A; p.(Arg771Gln) carriers in a large Amish sibship with Tatton-Brown-Rahman syndrome (TBRS), their mosaic father, and 15 TBRS patients with distinct pathogenic de novo DNMT3A variants. This defined widespread DNA hypomethylation at specific genomic sites enriched at locations annotated as genes involved in morphogenesis, development, differentiation, and malignancy predisposition pathways. TBRS patients also displayed highly accelerated DNA methylation aging. These findings were most marked in a carrier of the AML-associated driver mutation p.Arg882Cys. Our studies additionally defined phenotype-related accelerated and decelerated epigenetic aging in two histone methyltransferase disorders: NSD1 Sotos syndrome overgrowth disorder and KMT2D Kabuki syndrome growth impairment. Together, our findings provide fundamental new insights into aberrant epigenetic mechanisms, the role of epigenetic machinery maintenance, and determinants of biological aging in these growth disorders.

3.
Genome Med ; 11(1): 12, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30819258

RESUMO

BACKGROUND: Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1, the dosage-sensitive gene responsible for Smith-Magenis syndrome (deletion/haploinsufficiency) and Potocki-Lupski syndrome (duplication/triplosensitivity). METHODS: Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20. We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes. RESULTS: We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20. The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances. CONCLUSIONS: TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith-Magenis syndrome. Together with previously described cases, the clinical entity of TCF20-associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective.


Assuntos
Anormalidades Craniofaciais/genética , Deficiências do Desenvolvimento/genética , Mutação INDEL , Deficiência Intelectual/genética , Hipotonia Muscular/genética , Síndrome de Smith-Magenis/genética , Fatores de Transcrição/genética , Adolescente , Criança , Pré-Escolar , Anormalidades Craniofaciais/patologia , Deficiências do Desenvolvimento/patologia , Feminino , Humanos , Lactente , Deficiência Intelectual/patologia , Masculino , Hipotonia Muscular/patologia , Síndrome de Smith-Magenis/patologia , Fatores de Transcrição/metabolismo , Adulto Jovem
5.
Wellcome Open Res ; 3: 46, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29900417

RESUMO

Tatton-Brown-Rahman syndrome (TBRS; OMIM 615879), also known as the DNMT3A-overgrowth syndrome, is an overgrowth intellectual disability syndrome first described in 2014 with a report of 13 individuals with constitutive heterozygous DNMT3A variants. Here we have undertaken a detailed clinical study of 55 individuals with de novoDNMT3A variants, including the 13 previously reported individuals. An intellectual disability and overgrowth were reported in >80% of individuals with TBRS and were designated major clinical associations. Additional frequent clinical associations (reported in 20-80% individuals) included an evolving facial appearance with low-set, heavy, horizontal eyebrows and prominent upper central incisors; joint hypermobility (74%); obesity (weight ³2SD, 67%); hypotonia (54%); behavioural/psychiatric issues (most frequently autistic spectrum disorder, 51%); kyphoscoliosis (33%) and afebrile seizures (22%). One individual was diagnosed with acute myeloid leukaemia in teenage years. Based upon the results from this study, we present our current management for individuals with TBRS.

6.
Prenat Diagn ; 38(1): 33-43, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29096039

RESUMO

OBJECTIVE: Rare genetic disorders resulting in prenatal or neonatal death are genetically heterogeneous, but testing is often limited by the availability of fetal DNA, leaving couples without a potential prenatal test for future pregnancies. We describe our novel strategy of exome sequencing parental DNA samples to diagnose recessive monogenic disorders in an audit of the first 50 couples referred. METHOD: Exome sequencing was carried out in a consecutive series of 50 couples who had 1 or more pregnancies affected with a lethal or prenatal-onset disorder. In all cases, there was insufficient DNA for exome sequencing of the affected fetus. Heterozygous rare variants (MAF < 0.001) in the same gene in both parents were selected for analysis. Likely, disease-causing variants were tested in fetal DNA to confirm co-segregation. RESULTS: Parental exome analysis identified heterozygous pathogenic (or likely pathogenic) variants in 24 different genes in 26/50 couples (52%). Where 2 or more fetuses were affected, a genetic diagnosis was obtained in 18/29 cases (62%). In most cases, the clinical features were typical of the disorder, but in others, they result from a hypomorphic variant or represent the most severe form of a variable phenotypic spectrum. CONCLUSION: We conclude that exome sequencing of parental samples is a powerful strategy with high clinical utility for the genetic diagnosis of lethal or prenatal-onset recessive disorders. © 2017 The Authors Prenatal Diagnosis published by John Wiley & Sons Ltd.


Assuntos
Anormalidades Congênitas/genética , Doenças Genéticas Inatas/diagnóstico , Pais , Diagnóstico Pré-Natal/métodos , Sequenciamento Completo do Exoma , Feminino , Genes Recessivos , Humanos , Masculino , Gravidez
7.
Nat Genet ; 49(2): 249-255, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28067911

RESUMO

Bosma arhinia microphthalmia syndrome (BAMS) is an extremely rare and striking condition characterized by complete absence of the nose with or without ocular defects. We report here that missense mutations in the epigenetic regulator SMCHD1 mapping to the extended ATPase domain of the encoded protein cause BAMS in all 14 cases studied. All mutations were de novo where parental DNA was available. Biochemical tests and in vivo assays in Xenopus laevis embryos suggest that these mutations may behave as gain-of-function alleles. This finding is in contrast to the loss-of-function mutations in SMCHD1 that have been associated with facioscapulohumeral muscular dystrophy (FSHD) type 2. Our results establish SMCHD1 as a key player in nasal development and provide biochemical insight into its enzymatic function that may be exploited for development of therapeutics for FSHD.


Assuntos
Atresia das Cóanas/genética , Proteínas Cromossômicas não Histona/genética , Microftalmia/genética , Mutação de Sentido Incorreto/genética , Nariz/anormalidades , Animais , Linhagem Celular , Pré-Escolar , Epigênese Genética/genética , Feminino , Predisposição Genética para Doença/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Distrofia Muscular Facioescapuloumeral/genética , Xenopus laevis/genética
8.
Indian J Psychol Med ; 38(2): 142-6, 2016 Mar-Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27114627

RESUMO

INTRODUCTION: Neurocysticercosis (NCC) is the most common parasitic infection of man. In addition to a headache, seizures, and focal deficits, this is associated with significant cognitive dysfunction. Many studies revealed that the number and location of lesions are not always responsible for cognitive dysfunction. Cholinesterase and pseudocholinesterase are found in the walls of the cysticercus which could contribute to cholinergic depletion and thus cognitive dysfunction. PATIENTS AND METHODS: A total of 43 patients who presented with NCC were evaluated for cognitive deficits, as well as cholinesterase levels in cerebrospinal fluid (CSF) with control CSF from patients undergoing spinal anesthesia. Blood levels of interleukin-10 and tumor necrosis factor alpha were also estimated and correlated with cognitive deficits. RESULTS: There is a mild increase in the acetylcholinesterase in CSF of patients compared to controls, but it did not correlate with cognitive deficits. There is an increase in interleukins to a significant level which correlates with vesicular stage of the organism and cognitive impairment. The number of lesions also correlated with cognitive impairment even though the location did not. The domains of cognitive deficits seen are sustained attention, category fluency, verbal working memory, planning, set shifting, verbal learning, visual memory, and construction. DISCUSSION AND CONCLUSION: NCC is associated with multi-domain cognitive impairment correlates with vescicular stage, proinflammatory cytokines and number of lesions but not location, vesicular stage, and proinflammatory cytokines.

9.
Indian J Psychol Med ; 38(1): 56-61, 2016 Jan-Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27011404

RESUMO

INTRODUCTION: Vascular dementia consists of cognitive and functional impairment due to cerebrovascular brain injury. With reference to small vessel disease (SVD), even though the radiological evidence of SVD is present in a large number of persons above the age of 80 years, less than one-third of the people progress to dementia. Hence, if those factors are identified, we may be able to formulate strategies to protect that percentage of patients who progress to dementia. In this study, we have analyzed some genetic and nongenetic factors in patients with and without a cognitive impairment in the presence of radiological SVD. PATIENTS AND METHODS: Two hundred and ten patients who satisfied the criteria for the study were included. All medical comorbidities, demographic factors, substance abuse, etc., were documented and neuropsychological evaluation done. In addition, the genetic testing was done for the polymorphisms of TT, TC, and CC alleles of CYP11B2 based on the literature evidence of the association of CYP11B2 polymorphism and hypertension. RESULTS: This prospective hospital-based study revealed a significant relationship among hypertension, hyperhomocysteinemia, and severity of white matter changes but other comorbidities did not correlate. No significant correlation was seen between cognitive dysfunction and severity of white matter changes or genotypes TT, TC, and CC. However, TC genotype was more common in male hypertensives. Even though hypertension and hyperhomocysteinemia were associated with leukoaraiosis, none of the factors studied trigger conversion of these radiological changes to clinical cognitive impairment. DISCUSSION AND CONCLUSION: Severity of cerebral white matter changes seems to correlate with hypertension and hyperhomocysteinemia, however, none of the co-morbidities studied including the three polymorphisms of CYP11B2, that is, TT, TC, and CC seem to determine the conversion of leukoaraiosis to dementia.

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