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.

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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 [β6(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 β(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.

Sickle cell disease has a great variability of clinical and biological expression that depends on modulatory and environmental genetic factors. This variability in clinical and biological expression encourages us to look for predictors of severity. Hemoglobin F and its genetic determinants are influencing prognostic factors. The objectives of this study were to: determine the prevalence of the Senegal haplotype in homozygous sickle cell patients, study the relationship between this haplotype and the hemoglobin F level and evaluate its influence on the complications of the disease. This is a cross-sectional prospective study that included 100 homozygous sickle cell patients aged over 15 years. A questionnaire was used to collect epidemiological, clinical and biological variables. The hemoglobin F level was measured by capillary method and the analysis of point mutations by restriction fragment length polymorphism (RFLP). These data were collected and analyzed with the software Epi-info 7.2. A value p ≤ 0.05 was considered significant. The Senegal haplotype was found in 90% of patients, of whom 58% were homozygous for this mutation and 32% were heterozygous. The hemoglobin F level averaged 9.5% ± 8.3% and correlated statistically significantly with the allelic frequency. However, only bilary lithiasis correlated with the Senegal haplotype (p <0.005). This study confirms the homogeneity of the Senegal haplotype in the Senegalese sickle cell population and its influence on the synthesis of hemoglobin F. On the other hand, it revealed the existence of a relationship between the Senegal haplotype and bilary lithiasis suggesting the role of this haplotype in the protection against polymerization and hemolysis globally.

BackgroundHLA 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.MethodsHLA typing was carried in 93 healthy Mauritanian blood donors, using single specific primer amplification (PCR-SSP).ResultsOccurrences 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.ConclusionsThese results, in agreement with previous data using different tissues markers, underlined the ethnic heterogeneity of the Mauritanian population.