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1.
J Pediatr Hematol Oncol ; 43(5): e727-e735, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32947577

RESUMO

Fanconi anemia (FA) is the most common inherited bone marrow failure syndrome and presents with cytopenias, characteristic physical features, increased chromosomal breaks, and a higher risk of malignancy. Genetic features of this disease vary among different ethnic groups. We aimed to identify the incidence, outcome, overall condition, and genetic features of patients affected with FA in Lebanon to optimize management, identify the most common genes, describe new mutations, and offer prenatal diagnosis and counseling to the affected families. Over a period of 17 years, 40 patients with FA were identified in 2 major diagnostic laboratories in Lebanon. Information was obtained on their clinical course and outcome from their primary physician. DNA was available in 20 patients and was studied for underlying mutations. FANCA seemed to be the most frequent genetic alteration and 2 novel mutations, one each in FANCA and FANCG, were identified. Nine patients developed various malignancies and died. This is the first study looking at clinical and genetic features of FA in Lebanon, and points to the need for establishing a national and regional registry for this condition.


Assuntos
Proteína do Grupo de Complementação A da Anemia de Fanconi/genética , Proteína do Grupo de Complementação G da Anemia de Fanconi/genética , Anemia de Fanconi/genética , Adolescente , Adulto , Criança , Pré-Escolar , Anemia de Fanconi/epidemiologia , Feminino , Humanos , Líbano/epidemiologia , Masculino , Mutação , Adulto Jovem
2.
Hum Mutat ; 40(10): 1690-1699, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31033087

RESUMO

Ataxia-telangiectasia-like disorder (ATLD) is a rare genomic instability syndrome caused by biallelic variants of MRE11 (meiotic recombination 11) characterized by progressive cerebellar ataxia and typical karyotype abnormalities. These symptoms are common to those of ataxia-telangiectasia, which is consistent with the key role of MRE11 in ataxia-telangiectasia mutated (ATM) activation after DNA double-strand breaks. Three unrelated French patients were referred with ataxia. Only one had typical karyotype abnormalities. Unreported biallelic MRE11 variants were found in these three cases. Interestingly, one variant (c.424G>A) was present in two cases and haplotype analysis strongly suggested a French founder variant. Variants c.544G>A and c.314+4_314+7del lead to splice defects. The level of MRE11 in lymphoblastoid cell lines was consistently and dramatically reduced. Functional consequences were evaluated on activation of the ATM pathway via phosphorylation of ATM targets (KAP1 and CHK2), but no consistent defect was observed. However, an S-phase checkpoint activation defect after camptothecin was observed in these patients with ATLD. In conclusion, we report the first three French ATLD patients and a French founder variant, and propose an S-phase checkpoint activation study to evaluate the pathogenicity of MRE11 variants.


Assuntos
Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/etiologia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Linhagem Celular Tumoral , Criança , Suscetibilidade a Doenças , Feminino , Perfilação da Expressão Gênica , Estudos de Associação Genética , Predisposição Genética para Doença , Haplótipos , Humanos , Lactente , Proteína Homóloga a MRE11/genética , Proteína Homóloga a MRE11/metabolismo , Imageamento por Ressonância Magnética , Mutação , Fenótipo , Splicing de RNA , Pontos de Checagem da Fase S do Ciclo Celular/genética , Transdução de Sinais , Transcriptoma
3.
Hum Mutat ; 40(10): 1713-1730, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31050087

RESUMO

Ataxia-telangiectasia (A-T) is a recessive disorder caused by biallelic pathogenic variants of ataxia-telangiectasia mutated (ATM). This disease is characterized by progressive ataxia, telangiectasia, immune deficiency, predisposition to malignancies, and radiosensitivity. However, hypomorphic variants may be discovered associated with very atypical phenotypes, raising the importance of evaluating their pathogenic effects. In this study, multiple functional analyses were performed on lymphoblastoid cell lines from 36 patients, comprising 49 ATM variants, 24 being of uncertain significance. Thirteen patients with atypical phenotype and presumably hypomorphic variants were of particular interest to test strength of functional analyses and to highlight discrepancies with typical patients. Western-blot combined with transcript analyses allowed the identification of one missing variant, confirmed suspected splice defects and revealed unsuspected minor transcripts. Subcellular localization analyses confirmed the low level and abnormal cytoplasmic localization of ATM for most A-T cell lines. Interestingly, atypical patients had lower kinase defect and less altered cell-cycle distribution after genotoxic stress than typical patients. In conclusion, this study demonstrated the pathogenic effects of the 49 variants, highlighted the strength of KAP1 phosphorylation test for pathogenicity assessment and allowed the establishment of the Ataxia-TeLangiectasia Atypical Score to predict atypical phenotype. Altogether, we propose strategies for ATM variant detection and classification.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Ataxia Telangiectasia/diagnóstico , Ataxia Telangiectasia/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Variação Genética , Processamento Alternativo , Ciclo Celular , Linhagem Celular , Análise Mutacional de DNA , Estudos de Associação Genética/métodos , Genótipo , Humanos , Mutação , Fenótipo
4.
Ann Biol Clin (Paris) ; 72(3): 371-7, 2014.
Artigo em Francês | MEDLINE | ID: mdl-24876149

RESUMO

49, XXXXY syndrome is a rare sex chromosome aneuploidy occurring in 1:80 000-1:100 000 male births. Data on this aneuploidy in adulthood are limited, with most of the literature data based on paediatric patients. We report a new male patient whose 49, XXXXY diagnosis was formally made at the age of 54 years. So far, no medical follow-up was performed specifically for his condition. This man presented with facial features (epicanthus, hypertelorism, up-slanting palpebral fissures), microorchidism and features of chronic hypoandrogenism with muscular weakness, sparse body hair, dry skin with abnormal healing of skin wounds. Endocrine evaluation confirmed a hypergonadotropic hypogonadism. He had moderate intellectual deficiency with more affected verbal skills. A recent deep vein thrombosis was diagnosed in his left leg. Unusually, in addition to moderate deafness, he developed progressively a severe vision impairment leading to blindness. There have been very few reports of adult individuals with 49, XXXXY syndrome and this kind of report may contribute to improved management of prospective medical healthcare associated with this condition in older individuals.


Assuntos
Síndrome de Klinefelter/diagnóstico , Aneuploidia , Cegueira/diagnóstico , Surdez/diagnóstico , Pálpebras/anormalidades , Fácies , Humanos , Hipertelorismo/diagnóstico , Hipogonadismo/diagnóstico , Deficiência Intelectual/diagnóstico , Síndrome de Klinefelter/genética , Masculino , Pessoa de Meia-Idade
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