HLA class I (-A, -B, -C) and class II (-DR, -DQ) polymorphism in the Mauritanian population.

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.

Etiology and associated GJB2 mutations in Mauritanian children with non-syndromic hearing loss.

Origins of all hearing impairment forms may be divided into genetic mutations and acquired influence. Both carry damage to the inner ear structure resulting in a mild to profound dysfunction of the auditory system. The purpose of this study was to assess the different etiologies of deafness in two reference centers for hearing-impaired children in Nouakchott/Mauritania. Data on gender, age, consanguinity, etiology and family history of deafness were gathered by interviewing the custodians of 139 children with hearing loss. DNA of pupils with hereditary non-syndromic deafness was then screened for GJB2 mutations by sequencing methods. Postnatal hearing loss was found in 36 (25.8 %) out of the 139 children surveyed. The main etiologies of this group were infections caused by meningitis (12.9 %) and measles (2.8 %). Unknown and ototoxic origins accounted for, respectively, 5.7 and 3.5 %. In 103 (74.1 %) children, deafness was identified near after the time of birth and, therefore, presumed as congenital. 56.8 % of deaf children had consanguineous parents. Two GJB2 mutations, c.del35G with an allele frequency of 4.7 % and R32C (3.7 %) were detected. Infections such as meningitis and measles were the most prevalent causes of postnatal deafness. In cases of congenital hearing impairment, two GJB2 allele variants, i.e., del35G and R32C (3.7 %) were detected. Extended genetic testing is recommended for a more comprehensive determination of congenital causes.

Hb S [ß6(A3)Glu→Val, GAG>GTG] and ß-globin gene cluster haplotype distribution in Mauritania.

Of 1050 Mauritanian blood donors screened from the two main racial groups, i.e., the Moors and Black Africans, 60 were found to carry Hb S [ß6(A3)Glu→Val, GAG>GTG], giving a global frequency of 5.71%. The prevalence observed in the Black African Mauritanians (10.69%) is almost five times that found in the Moor group (2.25%). Four of the five main ß(S) haplotypes were detected in this study: Senegal (77.8%), Benin (8.8%), Arab-Indian (5.5%) and Bantu (4.4%). These data showed that Hb S is a serious public health problem in Mauritania. They also confirm the ethnic heterogeneity of the Mauritanian population.

Study of the T16189C variant and mitochondrial lineages in Tunisian and overall Mediterranean region.

The mitochondrial DNA (mtDNA) variant T16189C has been investigated in several metabolic diseases. In this study, we aimed to estimate the frequency of the T16189C variant in Tunisian and other Mediterranean populations and to evaluate the impact of this variant on the phylogeny of Mediterranean populations. Blood sample of 240 unrelated Tunisian subjects were recruited from several Tunisian localities. The hypervariable region 1 of the mtDNA were amplified and sequenced. Additional sequences (N = 4921) from Mediterranean populations were compiled from previous studies. The average frequency of T16189C variant in Tunisia (29%) is similar to that observed in North African and Near Eastern populations. Our findings showed positive correlation of the T16189C variant with Sub-Saharan and North African lineages, while a negative correlation was found with the Eurasian haplogroups, reaching its maximum with the Eurasian haplogroup H. The principal component analyses showed a high internal heterogeneity between Tunisian localities. At the Mediterranean scale, Tunisians are closer to North African (Algerian and Moroccan) and Near Eastern populations (Syrians and Palestinians) than to Europeans.

E23K variant in KCNJ11 gene is associated with susceptibility to type 2 diabetes in the Mauritanian population.

AIMS: Many genetic association studies reported the contribution of KCNJ11 gene to type 2 diabetes susceptibility in different populations. We aimed to evaluate the association between E23K variant of KCNJ11 and type 2 diabetes in the Mauritanian population. MATERIALS AND METHODS: We performed a case-control association study including 135 type 2 diabetes Mauritanian patients and 135 controls. Genotyping for the E23K variant was performed using a TaqMan allelic discrimination assay. RESULTS: We found significant association between KCNJ11 E23K variant and type 2 diabetes (Global model, OR=2.08, 95% CI=1.09-3.97, p=0.026). In the Moor ethnic group, E23K was also associated with type 2 diabetes in the general model (OR=2.08, 95% CI=1.09-3.97, p=0.026) and under the dominant model (OR=2.49, 95% CI=1.12-5.55, p=0.026). In the Mauritanians of African descent, KK genotype was not found. Besides, E23K variant was not associated with type 2 diabetes (OR=0.69, 95% CI=0.04-11.32, p=0.793). CONCLUSIONS: Our results revealed the risk of type 2 diabetes conferred by KCNJ11 E23K gene variant in the Mauritanian population.

Type 2 diabetes in Mauritania: prevalence of the undiagnosed diabetes, influence of family history and maternal effect.

AIM: We estimated the prevalence of undiagnosed diabetes, analyzed the influence of family history on the occurrence of T2D and evaluated its aggregation pattern in the Mauritanian population. METHODS: The prevalence of unknown diabetes was obtained using data compiled from 1278 Mauritanian adults applying a questionnaire and fasting serum glucose tests. Detailed family history of diabetes and clinical characteristics were gathered from 421 T2D patients. RESULTS: The prevalence of undiagnosed diabetes was 4.7 ± 1.2% in the studied population (3.1% in men and 6.4% in women). 27% of T2D patients reported at least one relative with diabetes. Association between family history and diabetes was higher among first degree compared to second degree relatives (p=0.003). We observed more probands with an affected mother than those who have a father with diabetes (p = 0.002), suggesting a preferential maternal effect which did not extend to second degree relatives. CONCLUSIONS: These results show that the prevalence of diabetes in the Mauritanian population could be higher than currently thought. Family history screening may be used in the management of this condition in Mauritania.