Allelic frequencies of 22 short tandem repeats loci and tri-allelic patterns of Penta D and TPOX identified in Gabonese population.

Short tandem repeats (STRs) are repeating DNA sequences used in forensic human identity testing and the diagnosis of aneuploidies. Many STRs like Penta D and TPOX are used routinely for paternity tests, but these tests are not widely used in sub-Saharan Africa. In this study we recruited individuals from Gabonese families seeking a paternity test. After DNA extraction from buccal swabs, we genotyped samples using a panel of 22 STRs. A total of 115 unrelated subjects from 39 families were included. Allele frequencies of the 22 STR loci were determined in unrelated Gabonese subjects. The most polymorphic loci were D21S11 (16 alleles) and FGA (17 alleles), while D3S1358 and TH01 loci were less polymorphic, with five alleles each. Deviation from Hardy-Weinberg equilibrium was observed for TPOX, D3S1358, CSFPO and D7S820 loci. We reported tri-allelic patterns that indicate aneuploidies at a combined frequency of 4% (4/115) with 3% for Penta D (1/35) and 3% for TPOX (3/102). Furthermore, we identified a new tri-allelic genotype 5-8-16 for the Penta D locus located on chromosome 21 in a healthy subject. In addition, we observed three tri-allelic variants of TPOX, located on chromosome 2, in healthy subjects, namely 8-10-11, 8-9-10, and 8-8-10. Our study revealed unsuspected polymorphic variations in Penta D and TPOX for the first time in Gabon, raising several questions about chromosomal disorders. Further population genetics studies are needed in Gabon to better characterize these variations, both qualitatively and quantitative.

Prevalence and factors associated to gestational diabetes mellitus among pregnant women in Libreville: a cross-sectional study.

Introduction: mainly occurring in low and middle income countries, gestational diabetes mellitus (GDM) represents 84% of hyperglycemia during pregnancy throughout the world. Moreover, being black is a risk factor to develop the disease. Our objective was to determine the prevalence and the associated factors of GDM in Libreville (Gabon). Methods: a cross-sectional study was carried out. Known diabetic women were excluded from the study and we had submitted asymptomatic pregnant women to a 2 steps 75g oral glucose tolerance test (T0-T2H), regardless of the stage of pregnancy at the moment of recruitment. The threshold for positivity was set at blood glucose level ≥ 8.5mmol/L World Health Organization (WHO 2013 threshold) and ≥ 7.8mmol/L (WHO 1999 threshold). Data were analyzed using Statview® for descriptive statistics, for both bivariate and multivariate analysis. Results: among 245 participants, we have found a GDM prevalence of 10.2% according to WHO 1999 threshold and 4.5% according to WHO 2013 threshold. Applying the WHO 1999 threshold, the associated factors were high maternal weight (p= 0.0498), overweight at recruitment (p=0.0246), personal history of GDM (p< 0.0001), age becomes an associated factor only if it is combined with high parity (p=0.0061). ceaserian-section and macrosomia were the two outcomes of GDM. Conclusion: Libreville has a high prevalence of GDM when the WHO 1999 criteria is compared to the WHO 2013 criteria. Discordance is also found with the identified associated factors. Further studies are needed to better appreciate gestational diabetes in Gabon.