RESUMEN
Purpose: Intraocular pressure leading to glaucoma is a major cause of childhood blindness in developing countries. In this study, we sought to identify gene variants potentially associated with primary congenital glaucoma (PCG) in the Mauritanian population. Methods: Using next-generation sequencing (NGS), a panel of PCG candidate genes was screened in a search for DNA mutations in four families with multiple occurrences of PCG. Results: Targeted exome sequencing analysis revealed predicted pathogenic mutations in four genes: CYP1B1 (c.217_218delTC, p.Ser73Valfs*150), MYOC (878C>A, p.T293K), NTF4 (c.601T>G, p.Cys201Gly), and WDR36 (c.2078A>G, p.Asn693Ser), each carried by a different family. Conclusions: Genetic variation associated with PCG in this study reflects the ethnic heterogeneity of the Mauritanian population. However, a larger cohort is needed to identify additional families carrying these mutations and confirm their biologic role.
Asunto(s)
Estudios de Asociación Genética , Glaucoma/congénito , Glaucoma/genética , Mutación/genética , Secuencia de Aminoácidos , Secuencia de Bases , Niño , Análisis Mutacional de ADN , Familia , Femenino , Pruebas Genéticas , Humanos , Masculino , Mauricio , Linaje , Péptidos/químicaRESUMEN
BACKGROUND: HLA antigens have been widely studied for their role in transplantation biology, human diseases and population diversity. The aim of this study was to provide the first profile of HLA class I and class II alleles in the Mauritanian population. METHODS: HLA typing was carried in 93 healthy Mauritanian blood donors, using single specific primer amplification (PCR-SSP). RESULTS: Occurrences of the main HLA class I (-A, -B, -C) and class II (-DR, -DQ) antigens in the general population showed that out of the 17 HLA-A allele groups detected, five main HLA-A allele groups: A*02 (18.42%), A*01 (14.04%), A*23 (14.04%), A*30 (13.16%) and A*29 (12.28%) were the most common identified along other 12 relatively minor allele groups. Twenty three allele groups were observed in the locus B of which B*07 (13.46%) was the most prevalent followed by B*15, B*35, B*08 and B*27 all, with a frequency between 7 to 8%. Three prevalent HLA-C allele groups (C*02: 35.09%, C*07: 20.19% and C*06: 13.6%) were detected. The main HLA class II observed allele groups were: DRB1*13 (27.42%), DRB1*03 (24.73%), DRB1*11 (13.98%), DQB1*03 (36.03%), DQB1*02 (22.06%) and DQB1*05 (18.8%). Except for few haplotype in class I (A*02-B*07: 4.45%, A*02-C02: 10%, A*23-C*02: 8.8%, B*07-C*02: 8.8%, B*15-C*02: 8.8%) and in class II (DRB1*13-DQB1*06: 11.94%, DRB1*03-DQB1*02:11.19% and DRB1*03-DQB1*03: 10.45%), the majority of locus combination were in the range of 2-3%. A single predominant haplotype C*02-DRB1*03 (16.67%) was found. CONCLUSIONS: These results, in agreement with previous data using different tissues markers, underlined the ethnic heterogeneity of the Mauritanian population.
Asunto(s)
Población Negra/genética , Genética de Población , Antígenos HLA-A/genética , Antígenos HLA-B/genética , Antígenos HLA-C/genética , Antígenos HLA-D/genética , Polimorfismo de Nucleótido Simple , Alelos , Femenino , Frecuencia de los Genes , Sitios Genéticos , Cadenas beta de HLA-DQ/genética , Cadenas HLA-DRB1/genética , Haplotipos , Humanos , Masculino , Mauritania , FilogeografíaRESUMEN
OBJECTIVE OF THE STUDY: Inborn lens opacity is the most frequent cause of childhood blindness. In this study, we aimed to define the presumed genetic cause of a congenital cataract present in a Mauritanian family over the last nine generations. METHODS: A family history of the disease and eye examination were carried out for the family members. Next-generation sequencing using a panel of 116 cataract underlying genes was selectively conducted on the proband's DNA. Nucleotide and amino acid changes and their impact on the phenotype were evaluated using various data analyzing software. RESULTS: Congenital nuclear cataract, with autosomal dominant mode, was observed in the family. All patients had consequences on their vision in the first 2 years of life. Genetic screening revealed a new mutation c.166A>C (p.Thr56Pro) in GJA8, encoding the Cx50 α-connexin protein. This mutation co-segregated in all patients and was not observed in the unaffected family members and controls. The predicted secondary structure impacted by p.Thr56Pro revealed a localized disruption, in the first extra membrane loop of the wild-type sheet, which is replaced in the mutant protein by a turn then a coil. This conformational change was functionally predicted as probably damaging. CONCLUSION: A new mutation (c.166A>C) in GJA8 underlying a nuclear congenital cataract was identified in this study. Its segregation with the phenotype might be useful as a predicting marker of the disease.