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1.
J Med Genet ; 61(6): 595-604, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38408845

RESUMO

BACKGROUND: Primary ciliary dyskinesia (PCD) is a rare airway disorder caused by defective motile cilia. Only male patients have been reported with pathogenic mutations in X-linked DNAAF6, which result in the absence of ciliary dynein arms, whereas their heterozygous mothers are supposedly healthy. Our objective was to assess the possible clinical and ciliary consequences of X-chromosome inactivation (XCI) in these mothers. METHODS: XCI patterns of six mothers of male patients with DNAAF6-related PCD were determined by DNA-methylation studies and compared with their clinical phenotype (6/6 mothers), as well as their ciliary phenotype (4/6 mothers), as assessed by immunofluorescence and high-speed videomicroscopy analyses. The mutated X chromosome was tracked to assess the percentage of cells with a normal inactivated DNAAF6 allele. RESULTS: The mothers' phenotypes ranged from absence of symptoms to mild/moderate or severe airway phenotypes, closely reflecting their XCI pattern. Analyses of the symptomatic mothers' airway ciliated cells revealed the coexistence of normal cells and cells with immotile cilia lacking dynein arms, whose ratio closely mirrored their XCI pattern. CONCLUSION: This study highlights the importance of searching for heterozygous pathogenic DNAAF6 mutations in all female relatives of male PCD patients with a DNAAF6 defect, as well as in females consulting for mild chronic respiratory symptoms. Our results also demonstrate that about one-third-ranging from 20% to 50%-normal ciliated airway cells sufficed to avoid severe PCD, a result paving the way for gene therapy.


Assuntos
Cílios , Inativação do Cromossomo X , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Cílios/patologia , Cílios/genética , Transtornos da Motilidade Ciliar/genética , Transtornos da Motilidade Ciliar/patologia , Metilação de DNA/genética , Dineínas/genética , Síndrome de Kartagener/genética , Síndrome de Kartagener/patologia , Mutação , Fenótipo , Inativação do Cromossomo X/genética
2.
Genet Med ; 26(6): 101081, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38293907

RESUMO

PURPOSE: Progressive inherited retinal degenerations (IRDs) affecting rods and cones are clinically and genetically heterogeneous and can lead to blindness with limited therapeutic options. The major gene defects have been identified in subjects of European and Asian descent with only few reports of North African descent. METHODS: Genome, targeted next-generation, and Sanger sequencing was applied to cohort of ∼4000 IRDs cases. Expression analyses were performed including Chip-seq database analyses, on human-derived retinal organoids (ROs), retinal pigment epithelium cells, and zebrafish. Variants' pathogenicity was accessed using 3D-modeling and/or ROs. RESULTS: Here, we identified a novel gene defect with three distinct pathogenic variants in UBAP1L in 4 independent autosomal recessive IRD cases from Tunisia. UBAP1L is expressed in the retinal pigment epithelium and retina, specifically in rods and cones, in line with the phenotype. It encodes Ubiquitin-associated protein 1-like, containing a solenoid of overlapping ubiquitin-associated domain, predicted to interact with ubiquitin. In silico and in vitro studies, including 3D-modeling and ROs revealed that the solenoid of overlapping ubiquitin-associated domain is truncated and thus ubiquitin binding most likely abolished secondary to all variants identified herein. CONCLUSION: Biallelic UBAP1L variants are a novel cause of IRDs, most likely enriched in the North African population.


Assuntos
Distrofias de Cones e Bastonetes , Linhagem , Peixe-Zebra , Humanos , Distrofias de Cones e Bastonetes/genética , Distrofias de Cones e Bastonetes/patologia , Masculino , Feminino , Peixe-Zebra/genética , Animais , Genes Recessivos , Epitélio Pigmentado da Retina/metabolismo , Epitélio Pigmentado da Retina/patologia , Mutação/genética , Células Fotorreceptoras Retinianas Cones/patologia , Células Fotorreceptoras Retinianas Cones/metabolismo , Retina/patologia , Retina/metabolismo , Adulto , Tunísia , Retinose Pigmentar/genética , Retinose Pigmentar/patologia , Fenótipo , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/patologia
3.
Am J Med Genet A ; 191(2): 445-458, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36369750

RESUMO

Chromosome 1p36 deletion syndrome (1p36DS) is one of the most common terminal deletion syndromes (incidence between 1/5000 and 1/10,000 live births in the American population), due to a heterozygous deletion of part of the short arm of chromosome 1. The 1p36DS is characterized by typical craniofacial features, developmental delay/intellectual disability, hypotonia, epilepsy, cardiomyopathy/congenital heart defect, brain abnormalities, hearing loss, eyes/vision problem, and short stature. The aim of our study was to (1) evaluate the incidence of the 1p36DS in the French population compared to 22q11.2 deletion syndrome and trisomy 21; (2) review the postnatal phenotype related to microarray data, compared to previously publish prenatal data. Thanks to a collaboration with the ACLF (Association des Cytogénéticiens de Langue Française), we have collected data of 86 patients constituting, to the best of our knowledge, the second-largest cohort of 1p36DS patients in the literature. We estimated an average of at least 10 cases per year in France. 1p36DS seems to be much less frequent than 22q11.2 deletion syndrome and trisomy 21. Patients presented mainly dysmorphism, microcephaly, developmental delay/intellectual disability, hypotonia, epilepsy, brain malformations, behavioral disorders, cardiomyopathy, or cardiovascular malformations and, pre and/or postnatal growth retardation. Cardiac abnormalities, brain malformations, and epilepsy were more frequent in distal deletions, whereas microcephaly was more common in proximal deletions. Mapping and genotype-phenotype correlation allowed us to identify four critical regions responsible for intellectual disability. This study highlights some phenotypic variability, according to the deletion position, and helps to refine the phenotype of 1p36DS, allowing improved management and follow-up of patients.


Assuntos
Síndrome de DiGeorge , Síndrome de Down , Epilepsia , Deficiência Intelectual , Microcefalia , Humanos , Cromossomos Humanos Par 1 , Hipotonia Muscular , Deleção Cromossômica , Fenótipo
4.
J Allergy Clin Immunol ; 150(6): 1545-1555, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35780935

RESUMO

BACKGROUND: Urticarial lesions are observed in both cutaneous and systemic disorders. Familial forms of urticarial syndromes are rare and can be encountered in systemic autoinflammatory diseases. OBJECTIVE: We sought to investigate a large family with dominantly inherited chronic urticarial lesions associated with hypercytokinemia. METHODS: We performed a genetic linkage analysis in 14 patients from a 5-generation family, as well as whole-exome sequencing, cytokine profiling, and transcriptomic analyses on samples from 2 patients. The identified candidate protein was studied after in vitro expression of the corresponding normal and mutated recombinant proteins. An unsupervised proteomic approach was used to unveil the associated protein network. RESULTS: The disease phenotype of the most affected family members is characterized by chronic urticarial flares associated with extremely high plasma levels of proinflammatory (IL-1ß, IL-6, and TNF-α) and anti-inflammatory (IL-10 and IL-1 receptor antagonist [IL-1RA]) cytokines, with no secondary organ dysfunction, no susceptibility to infections, no fever, and normal C-reactive protein levels. Monocyte transcriptomic analyses identified an immunotolerant profile in the most affected patient. The affected family members carried a loss-of-function mutation in RNF213 that encodes mysterin, a protein with a poorly known physiologic role. We identified the deubiquitinase CYLD, a major regulator of inflammation, as an RNF213 partner and showed that CYLD expression is inhibited by wild-type but not mutant RNF213. CONCLUSION: We identified a new entity characterized by chronic urticarial lesions associated with a clinically blunted hypercytokinemia. This disease, which is due to loss of function of RNF213, reveals mysterin's key role in the complex molecular network of innate immunity.


Assuntos
Síndrome da Liberação de Citocina , Proteômica , Humanos
5.
Clin Genet ; 101(3): 307-316, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34866188

RESUMO

Inverted duplication deletion 8p [invdupdel(8p)] is a complex and rare chromosomal rearrangement that combines a distal deletion and an inverted interstitial duplication of the short arm of chromosome 8. Carrier patients usually have developmental delay and intellectual disability (ID), associated with various cerebral and extra-cerebral malformations. Invdupdel(8p) is the most common recurrent chromosomal rearrangement in ID patients with anomalies of the corpus callosum (AnCC). Only a minority of invdupdel(8p) cases reported in the literature to date had both brain cerebral imaging and chromosomal microarray (CMA) with precise breakpoints of the rearrangements, making genotype-phenotype correlation studies for AnCC difficult. In this study, we report the clinical, radiological, and molecular data from 36 new invdupdel(8p) cases including three fetuses and five individuals from the same family, with breakpoints characterized by CMA. Among those, 97% (n = 32/33) of patients presented with mild to severe developmental delay/ID and 34% had seizures with mean age of onset of 3.9 years (2 months-9 years). Moreover, out of the 24 patients with brain MRI and 3 fetuses with neuropathology analysis, 63% (n = 17/27) had AnCC. We review additional data from 99 previously published patients with invdupdel(8p) and compare data of 17 patients from the literature with both CMA analysis and brain imaging to refine genotype-phenotype correlations for AnCC. This led us to refine a region of 5.1 Mb common to duplications of patients with AnCC and discuss potential candidate genes within this region.


Assuntos
Deficiência Intelectual , Leucoencefalopatias , Deleção Cromossômica , Inversão Cromossômica , Cromossomos Humanos Par 8 , Corpo Caloso/diagnóstico por imagem , Estudos de Associação Genética , Humanos , Deficiência Intelectual/diagnóstico por imagem , Deficiência Intelectual/genética , Leucoencefalopatias/genética , Fenótipo , Trissomia
6.
Clin Genet ; 102(2): 117-122, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35470444

RESUMO

BRD4 is part of a multiprotein complex involved in loading the cohesin complex onto DNA, a fundamental process required for cohesin-mediated loop extrusion and formation of Topologically Associating Domains. Pathogenic variations in this complex have been associated with a growing number of syndromes, collectively known as cohesinopathies, the most classic being Cornelia de Lange syndrome. However, no cohort study has been conducted to delineate the clinical and molecular spectrum of BRD4-related disorder. We formed an international collaborative study, and collected 14 new patients, including two fetuses. We performed phenotype and genotype analysis, integrated prenatal findings from fetopathological examinations, phenotypes of pediatric patients and adults. We report the first cohort of patients with BRD4-related disorder and delineate the dysmorphic features at different ages. This work extends the phenotypic spectrum of cohesinopathies and characterize a new clinically relevant and recognizable pattern, distinguishable from the other cohesinopathies.


Assuntos
Síndrome de Cornélia de Lange , Proteínas Nucleares , Proteínas de Ciclo Celular/genética , Criança , Síndrome de Cornélia de Lange/diagnóstico , Síndrome de Cornélia de Lange/genética , Síndrome de Cornélia de Lange/patologia , Feminino , Genômica , Humanos , Mutação , Proteínas Nucleares/genética , Fenótipo , Gravidez , Fatores de Transcrição/genética
7.
Am J Med Genet A ; 185(10): 3057-3061, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34043868

RESUMO

Balanced translocations are associated with a risk of transmission of unbalanced chromosomal rearrangements in the offspring. Such inherited chromosomal abnormalities are typically non-mosaic as they are present in the germline. We report the recurrence in two siblings of a mosaicism for a chromosomal rearrangement inherited from their asymptomatic father who carried a balanced t(2;11)(q35;q25) translocation. Both siblings exhibited a similar phenotype including intellectual disability, dysmorphic features, kyphoscoliosis, and cervical spinal stenosis. Karyotyping, fluorescence in situ hybridization and SNP array analysis of blood lymphocytes of both siblings identified two cell lines: one carrying a 2q35q37.3 duplication and a 11q25qter deletion (~90% cells), and one carrying an 11q uniparental isodisomy of maternal origin (~10% cells). We hypothesize that these mosaics were related to a postzygotic rescue mechanism which unexpectedly recurred in both siblings.


Assuntos
Anormalidades Múltiplas/genética , Deficiência Intelectual/genética , Cifose/genética , Escoliose/genética , Dissomia Uniparental , Anormalidades Múltiplas/patologia , Vértebras Cervicais/patologia , Bandeamento Cromossômico , Deleção Cromossômica , Cromossomos/genética , Cromossomos Humanos Par 11/genética , Cromossomos Humanos Par 2/genética , Feminino , Predisposição Genética para Doença , Humanos , Hibridização in Situ Fluorescente , Deficiência Intelectual/patologia , Cariotipagem , Cifose/patologia , Masculino , Mosaicismo , Escoliose/patologia , Irmãos , Translocação Genética/genética
8.
J Med Genet ; 57(3): 160-168, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31586944

RESUMO

BACKGROUND: The type 1 insulin-like growth factor receptor (IGF1R) is a keystone of fetal growth regulation by mediating the effects of IGF-I and IGF-II. Recently, a cohort of patients carrying an IGF1R defect was described, from which a clinical score was established for diagnosis. We assessed this score in a large cohort of patients with identified IGF1R defects, as no external validation was available. Furthermore, we aimed to develop a functional test to allow the classification of variants of unknown significance (VUS) in vitro. METHODS: DNA was tested for either deletions or single nucleotide variant (SNV) and the phosphorylation of downstream pathways studied after stimulation with IGF-I by western blot analysis of fibroblast of nine patients. RESULTS: We detected 21 IGF1R defects in 35 patients, including 8 deletions and 10 heterozygous, 1 homozygous and 1 compound-heterozygous SNVs. The main clinical characteristics of these patients were being born small for gestational age (90.9%), short stature (88.2%) and microcephaly (74.1%). Feeding difficulties and varying degrees of developmental delay were highly prevalent (54.5%). There were no differences in phenotypes between patients with deletions and SNVs of IGF1R. Functional studies showed that the SNVs tested were associated with decreased AKT phosphorylation. CONCLUSION: We report eight new pathogenic variants of IGF1R and an original case with a homozygous SNV. We found the recently proposed clinical score to be accurate for the diagnosis of IGF1R defects with a sensitivity of 95.2%. We developed an efficient functional test to assess the pathogenicity of SNVs, which is useful, especially for VUS.


Assuntos
Anormalidades Múltiplas/genética , Desenvolvimento Fetal/genética , Retardo do Crescimento Fetal/genética , Transtornos do Crescimento/genética , Receptor IGF Tipo 1/genética , Anormalidades Múltiplas/epidemiologia , Anormalidades Múltiplas/fisiopatologia , Adolescente , Criança , Nanismo/genética , Nanismo/fisiopatologia , Feminino , Retardo do Crescimento Fetal/epidemiologia , Retardo do Crescimento Fetal/fisiopatologia , Transtornos do Crescimento/epidemiologia , Transtornos do Crescimento/fisiopatologia , Heterozigoto , Homozigoto , Humanos , Recém-Nascido Pequeno para a Idade Gestacional/crescimento & desenvolvimento , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like II/genética , Masculino , Microcefalia/genética , Microcefalia/fisiopatologia , Mutação de Sentido Incorreto/genética , Linhagem , Polimorfismo de Nucleotídeo Único/genética , Receptores de Somatomedina/genética
9.
J Med Genet ; 57(5): 301-307, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-30287593

RESUMO

BACKGROUND: The clinical significance of 16p13.11 duplications remains controversial while frequently detected in patients with developmental delay (DD), intellectual deficiency (ID) or autism spectrum disorder (ASD). Previously reported patients were not or poorly characterised. The absence of consensual recommendations leads to interpretation discrepancy and makes genetic counselling challenging. This study aims to decipher the genotype-phenotype correlations to improve genetic counselling and patients' medical care. METHODS: We retrospectively analysed data from 16 013 patients referred to 12 genetic centers for DD, ID or ASD, and who had a chromosomal microarray analysis. The referring geneticists of patients for whom a 16p13.11 duplication was detected were asked to complete a questionnaire for detailed clinical and genetic data for the patients and their parents. RESULTS: Clinical features are mainly speech delay and learning disabilities followed by ASD. A significant risk of cardiovascular disease was noted. About 90% of the patients inherited the duplication from a parent. At least one out of four parents carrying the duplication displayed a similar phenotype to the propositus. Genotype-phenotype correlations show no impact of the size of the duplicated segment on the severity of the phenotype. However, NDE1 and miR-484 seem to have an essential role in the neurocognitive phenotype. CONCLUSION: Our study shows that 16p13.11 microduplications are likely pathogenic when detected in the context of DD/ID/ASD and supports an essential role of NDE1 and miR-484 in the neurocognitive phenotype. Moreover, it suggests the need for cardiac evaluation and follow-up and a large study to evaluate the aortic disease risk.


Assuntos
Transtorno do Espectro Autista/genética , Deficiências do Desenvolvimento/genética , Deficiência Intelectual/genética , MicroRNAs/genética , Proteínas Associadas aos Microtúbulos/genética , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Adolescente , Adulto , Transtorno do Espectro Autista/patologia , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/patologia , Criança , Pré-Escolar , Cromossomos Humanos Par 16/genética , Deficiências do Desenvolvimento/patologia , Feminino , Duplicação Gênica/genética , Estudos de Associação Genética , Humanos , Lactente , Deficiência Intelectual/patologia , Masculino , Fenótipo , Fatores de Risco , Adulto Jovem
10.
Int J Mol Sci ; 22(15)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34360642

RESUMO

The purpose of this work was to identify the gene defect underlying a relatively mild rod-cone dystrophy (RCD), lacking disease-causing variants in known genes implicated in inherited retinal disorders (IRD), and provide transcriptomic and immunolocalization data to highlight the best candidate. The DNA of the female patient originating from a consanguineous family revealed no large duplication or deletion, but several large homozygous regions. In one of these, a homozygous frameshift variant, c.244_246delins17 p.(Trp82Valfs*4); predicted to lead to a nonfunctional protein, was identified in CCDC51. CCDC51 encodes the mitochondrial coiled-coil domain containing 51 protein, also called MITOK. MITOK ablation causes mitochondrial dysfunction. Here we show for the first time that CCDC51/MITOK localizes in the retina and more specifically in the inner segments of the photoreceptors, well known to contain mitochondria. Mitochondrial proteins have previously been implicated in IRD, although usually in association with syndromic disease, unlike our present case. Together, our findings add another ultra-rare mutation implicated in non-syndromic IRD, whose pathogenic mechanism in the retina needs to be further elucidated.


Assuntos
Distrofias de Cones e Bastonetes/patologia , Genes Recessivos , Proteínas Mitocondriais/genética , Mutação , Canais de Potássio/genética , Adulto , Distrofias de Cones e Bastonetes/etiologia , Distrofias de Cones e Bastonetes/metabolismo , Feminino , Humanos , Masculino , Linhagem , Fenótipo
11.
Hum Mol Genet ; 27(7): 1228-1240, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29373757

RESUMO

SOX8 is an HMG-box transcription factor closely related to SRY and SOX9. Deletion of the gene encoding Sox8 in mice causes reproductive dysfunction but the role of SOX8 in humans is unknown. Here, we show that SOX8 is expressed in the somatic cells of the early developing gonad in the human and influences human sex determination. We identified two individuals with 46, XY disorders/differences in sex development (DSD) and chromosomal rearrangements encompassing the SOX8 locus and a third individual with 46, XY DSD and a missense mutation in the HMG-box of SOX8. In vitro functional assays indicate that this mutation alters the biological activity of the protein. As an emerging body of evidence suggests that DSDs and infertility can have common etiologies, we also analysed SOX8 in a cohort of infertile men (n = 274) and two independent cohorts of women with primary ovarian insufficiency (POI; n = 153 and n = 104). SOX8 mutations were found at increased frequency in oligozoospermic men (3.5%; P < 0.05) and POI (5.06%; P = 4.5 × 10-5) as compared with fertile/normospermic control populations (0.74%). The mutant proteins identified altered SOX8 biological activity as compared with the wild-type protein. These data demonstrate that SOX8 plays an important role in human reproduction and SOX8 mutations contribute to a spectrum of phenotypes including 46, XY DSD, male infertility and 46, XX POI.


Assuntos
Transtornos 46, XX do Desenvolvimento Sexual/genética , Transtorno 46,XY do Desenvolvimento Sexual/genética , Mutação de Sentido Incorreto , Oligospermia/genética , Insuficiência Ovariana Primária/genética , Fatores de Transcrição SOXE/genética , Adolescente , Criança , Feminino , Humanos , Masculino
12.
Genet Med ; 22(11): 1887-1891, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32565546

RESUMO

PURPOSE: Abnormality of the corpus callosum (AbnCC) is etiologically a heterogeneous condition and the prognosis in prenatally diagnosed cases is difficult to predict. The purpose of our research was to establish the diagnostic yield using chromosomal microarray (CMA) and exome sequencing (ES) in cases with prenatally diagnosed isolated (iAbnCC) and nonisolated AbnCC (niAbnCC). METHODS: CMA and prenatal trio ES (pES) were done on 65 fetuses with iAbnCC and niAbnCC. Only pathogenic gene variants known to be associated with AbnCC and/or intellectual disability were considered. RESULTS: pES results were available within a median of 21.5 days (9-53 days). A pathogenic single-nucleotide variant (SNV) was identified in 12 cases (18%) and a pathogenic CNV was identified in 3 cases (4.5%). Thus, the genetic etiology was determined in 23% of cases. In all diagnosed cases, the results provided sufficient information regarding the neurodevelopmental prognosis and helped the parents to make an informed decision regarding the outcome of the pregnancy. CONCLUSION: Our results show the significant diagnostic and prognostic contribution of CMA and pES in cases with prenatally diagnosed AbnCC. Further prospective cohort studies with long-term follow-up of the born children will be needed to provide accurate prenatal counseling after a negative pES result.


Assuntos
Corpo Caloso , Exoma , Criança , Corpo Caloso/diagnóstico por imagem , Exoma/genética , Feminino , Feto/diagnóstico por imagem , Humanos , Gravidez , Estudos Prospectivos , Ultrassonografia Pré-Natal
13.
Genet Med ; 21(3): 553-563, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29997391

RESUMO

PURPOSE: To investigate the genetic basis of congenital ataxias (CAs), a unique group of cerebellar ataxias with a nonprogressive course, in 20 patients from consanguineous families, and to identify new CA genes. METHODS: Singleton -exome sequencing on these 20 well-clinically characterized CA patients. We first checked for rare homozygous pathogenic variants, then, for variants from a list of genes known to be associated with CA or very early-onset ataxia, regardless of their mode of inheritance. Our replication cohort of 180 CA patients was used to validate the new CA genes. RESULTS: We identified a causal gene in 16/20 families: six known CA genes (7 patients); four genes previously implicated in another neurological phenotype (7 patients); two new candidate genes (2 patients). Despite the consanguinity, 4/20 patients harbored a heterozygous de novo pathogenic variant. CONCLUSION: Singleton exome sequencing in 20 consanguineous CA families led to molecular diagnosis in 80% of cases. This study confirms the genetic heterogeneity of CA and identifies two new candidate genes (PIGS and SKOR2). Our work illustrates the diversity of the pathophysiological pathways in CA, and highlights the pathogenic link between some CA and early infantile epileptic encephalopathies related to the same genes (STXBP1, BRAT1, CACNA1A and CACNA2D2).


Assuntos
Ataxia/genética , Ataxia Cerebelar/genética , Espasmos Infantis/genética , Adolescente , Ataxia/fisiopatologia , Criança , Pré-Escolar , Estudos de Coortes , Exoma/genética , Feminino , França , Heterogeneidade Genética , Predisposição Genética para Doença/genética , Genótipo , Humanos , Masculino , Mutação/genética , Fenótipo , Sequenciamento do Exoma/métodos , Adulto Jovem
14.
Prenat Diagn ; 39(11): 986-992, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31273809

RESUMO

OBJECTIVE: Uniparental disomy (UPD) testing is currently recommended during pregnancy in fetuses carrying a balanced Robertsonian translocation (ROB) involving chromosome 14 or 15, both chromosomes containing imprinted genes. The overall risk that such a fetus presents a UPD has been previously estimated to be around ~0.6-0.8%. However, because UPD are rare events and this estimate has been calculated from a number of studies of limited size, we have reevaluated the risk of UPD in fetuses for whom one of the parents was known to carry a nonhomologous ROB (NHROB). METHOD: We focused our multicentric study on NHROB involving chromosome 14 and/or 15. A total of 1747 UPD testing were performed in fetuses during pregnancy for the presence of UPD(14) and/or UPD(15). RESULT: All fetuses were negative except one with a UPD(14) associated with a maternally inherited rob(13;14). CONCLUSION: Considering these data, the risk of UPD following prenatal diagnosis of an inherited ROB involving chromosome 14 and/or 15 could be estimated to be around 0.06%, far less than the previous estimation. Importantly, the risk of miscarriage following an invasive prenatal sampling is higher than the risk of UPD. Therefore, we do not recommend prenatal testing for UPD for these pregnancies and parents should be reassured.


Assuntos
Cromossomos Humanos Par 14 , Cromossomos Humanos Par 15 , Diagnóstico Pré-Natal , Translocação Genética , Dissomia Uniparental , Adulto , Feminino , Humanos , Masculino , Gravidez , Estudos Retrospectivos , Medição de Risco
15.
J Med Genet ; 55(3): 205-213, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29223973

RESUMO

BACKGROUND: The 11p15 region contains two clusters of imprinted genes. Opposite genetic and epigenetic anomalies of this region result in two distinct growth disturbance syndromes: Beckwith-Wiedemann (BWS) and Silver-Russell syndromes (SRS). Cytogenetic rearrangements within this region represent less than 3% of SRS and BWS cases. Among these, 11p15 duplications were infrequently reported and interpretation of their pathogenic effects is complex. OBJECTIVES: To report cytogenetic and methylation analyses in a cohort of patients with SRS/BWS carrying 11p15 duplications and establish genotype/phenotype correlations. METHODS: From a cohort of patients with SRS/BWS with an abnormal methylation profile (using ASMM-RTQ-PCR), we used SNP-arrays to identify and map the 11p15 duplications. We report 19 new patients with SRS (n=9) and BWS (n=10) carrying de novo or familial 11p15 duplications, which completely or partially span either both telomeric and centromeric domains or only one domain. RESULTS: Large duplications involving one complete domain or both domains are associated with either SRS or BWS, depending on the parental origin of the duplication. Genotype-phenotype correlation studies of partial duplications within the telomeric domain demonstrate the prominent role of IGF2, rather than H19, in the control of growth. Furthermore, it highlights the role of CDKN1C within the centromeric domain and suggests that the expected overexpression of KCNQ1OT1 from the paternal allele (in partial paternal duplications, excluding CDKN1C) does not affect the expression of CDKN1C. CONCLUSIONS: The phenotype associated with 11p15 duplications depends on the size, genetic content, parental inheritance and imprinting status. Identification of these rare duplications is crucial for genetic counselling.


Assuntos
Síndrome de Beckwith-Wiedemann/genética , Duplicação Gênica/genética , Impressão Molecular , Síndrome de Silver-Russell/genética , Adulto , Síndrome de Beckwith-Wiedemann/patologia , Centrômero/genética , Aberrações Cromossômicas , Cromossomos Humanos Par 11/genética , Inibidor de Quinase Dependente de Ciclina p57/genética , Análise Citogenética , Feminino , Humanos , Fator de Crescimento Insulin-Like II/genética , Masculino , Mutação , Fenótipo , Síndrome de Silver-Russell/patologia , Telômero/genética
16.
Am J Hum Genet ; 97(5): 691-707, 2015 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-26544804

RESUMO

The genomic duplication associated with Potocki-Lupski syndrome (PTLS) maps in close proximity to the duplication associated with Charcot-Marie-Tooth disease type 1A (CMT1A). PTLS is characterized by hypotonia, failure to thrive, reduced body weight, intellectual disability, and autistic features. CMT1A is a common autosomal dominant distal symmetric peripheral polyneuropathy. The key dosage-sensitive genes RAI1 and PMP22 are respectively associated with PTLS and CMT1A. Recurrent duplications accounting for the majority of subjects with these conditions are mediated by nonallelic homologous recombination between distinct low-copy repeat (LCR) substrates. The LCRs flanking a contiguous genomic interval encompassing both RAI1 and PMP22 do not share extensive homology; thus, duplications encompassing both loci are rare and potentially generated by a different mutational mechanism. We characterized genomic rearrangements that simultaneously duplicate PMP22 and RAI1, including nine potential complex genomic rearrangements, in 23 subjects by high-resolution array comparative genomic hybridization and breakpoint junction sequencing. Insertions and microhomologies were found at the breakpoint junctions, suggesting potential replicative mechanisms for rearrangement formation. At the breakpoint junctions of these nonrecurrent rearrangements, enrichment of repetitive DNA sequences was observed, indicating that they might predispose to genomic instability and rearrangement. Clinical evaluation revealed blended PTLS and CMT1A phenotypes with a potential earlier onset of neuropathy. Moreover, additional clinical findings might be observed due to the extra duplicated material included in the rearrangements. Our genomic analysis suggests replicative mechanisms as a predominant mechanism underlying PMP22-RAI1 contiguous gene duplications and provides further evidence supporting the role of complex genomic architecture in genomic instability.


Assuntos
Doença de Charcot-Marie-Tooth/genética , Transtornos Cromossômicos/genética , Duplicação Cromossômica/genética , Cromossomos Humanos Par 17/genética , Duplicação Gênica , Rearranjo Gênico , Proteínas da Mielina/genética , Fatores de Transcrição/genética , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Doença de Charcot-Marie-Tooth/patologia , Criança , Pré-Escolar , Transtornos Cromossômicos/patologia , Hibridização Genômica Comparativa , Feminino , Seguimentos , Genoma Humano , Genômica/métodos , Humanos , Lactente , Masculino , Modelos Genéticos , Fenótipo , Prognóstico , Recombinação Genética , Transativadores
17.
Am J Med Genet A ; 176(1): 151-155, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29130637

RESUMO

A congenital myasthenia was suspected in two unrelated children with very similar phenotypes including several episodes of severe dyspnea. Both children had a 10q11.2 deletion revealed by Single Nucleotide Polymorphisms array or by Next Generation Sequencing analysis. The deletion was inherited from the healthy mother in the first case. These deletions unmasked a recessive mutation at the same locus in both cases, but in two different genes: CHAT and SLC18A3.


Assuntos
Colina O-Acetiltransferase/genética , Deleção Cromossômica , Cromossomos Humanos Par 10 , Genes Recessivos , Mutação , Síndromes Miastênicas Congênitas/diagnóstico , Síndromes Miastênicas Congênitas/genética , Fenótipo , Proteínas Vesiculares de Transporte de Acetilcolina/genética , Sequência de Aminoácidos , Feminino , Estudos de Associação Genética , Humanos , Hibridização in Situ Fluorescente , Lactente , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único
18.
Brain ; 140(5): 1316-1336, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28379373

RESUMO

Mutations in SCN2A, a gene encoding the voltage-gated sodium channel Nav1.2, have been associated with a spectrum of epilepsies and neurodevelopmental disorders. Here, we report the phenotypes of 71 patients and review 130 previously reported patients. We found that (i) encephalopathies with infantile/childhood onset epilepsies (≥3 months of age) occur almost as often as those with an early infantile onset (<3 months), and are thus more frequent than previously reported; (ii) distinct phenotypes can be seen within the late onset group, including myoclonic-atonic epilepsy (two patients), Lennox-Gastaut not emerging from West syndrome (two patients), and focal epilepsies with an electrical status epilepticus during slow sleep-like EEG pattern (six patients); and (iii) West syndrome constitutes a common phenotype with a major recurring mutation (p.Arg853Gln: two new and four previously reported children). Other known phenotypes include Ohtahara syndrome, epilepsy of infancy with migrating focal seizures, and intellectual disability or autism without epilepsy. To assess the response to antiepileptic therapy, we retrospectively reviewed the treatment regimen and the course of the epilepsy in 66 patients for which well-documented medical information was available. We find that the use of sodium channel blockers was often associated with clinically relevant seizure reduction or seizure freedom in children with early infantile epilepsies (<3 months), whereas other antiepileptic drugs were less effective. In contrast, sodium channel blockers were rarely effective in epilepsies with later onset (≥3 months) and sometimes induced seizure worsening. Regarding the genetic findings, truncating mutations were exclusively seen in patients with late onset epilepsies and lack of response to sodium channel blockers. Functional characterization of four selected missense mutations using whole cell patch-clamping in tsA201 cells-together with data from the literature-suggest that mutations associated with early infantile epilepsy result in increased sodium channel activity with gain-of-function, characterized by slowing of fast inactivation, acceleration of its recovery or increased persistent sodium current. Further, a good response to sodium channel blockers clinically was found to be associated with a relatively small gain-of-function. In contrast, mutations in patients with late-onset forms and an insufficient response to sodium channel blockers were associated with loss-of-function effects, including a depolarizing shift of voltage-dependent activation or a hyperpolarizing shift of channel availability (steady-state inactivation). Our clinical and experimental data suggest a correlation between age at disease onset, response to sodium channel blockers and the functional properties of mutations in children with SCN2A-related epilepsy.


Assuntos
Epilepsia/tratamento farmacológico , Epilepsia/genética , Epilepsia/fisiopatologia , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Canal de Sódio Disparado por Voltagem NAV1.2/fisiologia , Transtornos do Neurodesenvolvimento/genética , Bloqueadores dos Canais de Sódio/uso terapêutico , Adolescente , Adulto , Idade de Início , Criança , Pré-Escolar , Dinamarca/epidemiologia , Epilepsia/epidemiologia , Feminino , Humanos , Lactente , Masculino , Mutação , Fenótipo , Adulto Jovem
19.
Hum Mutat ; 38(1): 105-111, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27701793

RESUMO

The 11p15 region harbors the IGF2/H19 imprinted domain, implicated in fetal and postnatal growth. Silver-Russell syndrome (SRS) is characterized by fetal and postnatal growth failure, and is caused principally by hypomethylation of the 11p15 imprinting control region 1 (ICR1). However, the mechanisms leading to ICR1 hypomethylation remain unknown. Maternally inherited genetic defects affecting the ICR1 domain have been associated with ICR1 hypermethylation and Beckwith-Wiedemann syndrome (an overgrowth syndrome, the clinical and molecular mirror of SRS), and paternal deletions of IGF2 enhancers have been detected in four SRS patients. However, no paternal deletions of ICR1 have ever been associated with hypomethylation of the IGF2/H19 domain in SRS. We screened for new genetic defects within the ICR1 in a cohort of 234 SRS patients with hypomethylated IGF2/H19 domain. We report deletions close to the boundaries of ICR1 on the paternal allele in one familial and two sporadic cases of SRS with ICR1 hypomethylation. These deletions are associated with hypomethylation of the remaining CBS, and decreased IGF2 expression. These results suggest that these regions are most likely required to maintain methylation after fertilization. We estimate these anomalies to occur in about 1% of SRS cases with ICR1 hypomethylation.


Assuntos
Cromossomos Humanos Par 11 , Metilação de DNA , Impressão Genômica , Fator de Crescimento Insulin-Like II/genética , RNA Longo não Codificante/genética , Deleção de Sequência , Síndrome de Silver-Russell/genética , Pré-Escolar , Feminino , Fibroblastos , Expressão Gênica , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Masculino , Linhagem
20.
Hum Genet ; 136(4): 463-479, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28283832

RESUMO

Subtelomeric 1q43q44 microdeletions cause a syndrome associating intellectual disability, microcephaly, seizures and anomalies of the corpus callosum. Despite several previous studies assessing genotype-phenotype correlations, the contribution of genes located in this region to the specific features of this syndrome remains uncertain. Among those, three genes, AKT3, HNRNPU and ZBTB18 are highly expressed in the brain and point mutations in these genes have been recently identified in children with neurodevelopmental phenotypes. In this study, we report the clinical and molecular data from 17 patients with 1q43q44 microdeletions, four with ZBTB18 mutations and seven with HNRNPU mutations, and review additional data from 37 previously published patients with 1q43q44 microdeletions. We compare clinical data of patients with 1q43q44 microdeletions with those of patients with point mutations in HNRNPU and ZBTB18 to assess the contribution of each gene as well as the possibility of epistasis between genes. Our study demonstrates that AKT3 haploinsufficiency is the main driver for microcephaly, whereas HNRNPU alteration mostly drives epilepsy and determines the degree of intellectual disability. ZBTB18 deletions or mutations are associated with variable corpus callosum anomalies with an incomplete penetrance. ZBTB18 may also contribute to microcephaly and HNRNPU to thin corpus callosum, but with a lower penetrance. Co-deletion of contiguous genes has additive effects. Our results confirm and refine the complex genotype-phenotype correlations existing in the 1qter microdeletion syndrome and define more precisely the neurodevelopmental phenotypes associated with genetic alterations of AKT3, ZBTB18 and HNRNPU in humans.


Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 1 , Ribonucleoproteínas Nucleares Heterogêneas/genética , Mutação , Transtornos do Neurodesenvolvimento/genética , Fenótipo , Proteínas Repressoras/genética , Humanos
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