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BackgroundThe inter-individual genetic polymorphism of cytochrome P450 enzymes (CYP), involved in the metabolism of many drugs, partly modulates drug response and toxicity. Single nucleotide polymorphisms of CYP2B6 for example, G516T have been implicated in high- and sub-therapeutic plasma concentration of the current antimalarial, HIV and TB first-line drugs in various geographical regions and thus undermines effective disease management. At present, there is no data on the frequency of CYP2B6 c.516G>T among the Congolese population, despite a significant number of people undergoing antimalarial, HIV and TB treatment that relies on CYP2B6-based drug clearance or activation.MethodsA total of 418 patients with HIV-1 mono-infection, HIV-1 +TB coinfection and P. falciparum infection were genotyped for CYP2B6 c.516G>T polymorphism using PCR-RFLP. The frequencies of the alleles as well as the genotypes (GG, GT and TT) were determined.ResultsThe frequency of CYP2B6 c.516G>T polymorphism was 69% and frequency of G and T alleles were 45% and 55%, respectively. 17.0% (49/288) of participants were GG (extensive metaboliser), 55.2% (159/288) of participants were GT (intermediate metaboliser) and 27.8% (80/288) of participants were TT (poor metabolisers).ConclusionThis study highlights CYP2B6 c.G516T polymorphism as a potential determinant of drug response and toxicity among the Congolese population, particularly those undergoing antiretroviral, malaria and tuberculosis treatment within the current first-line drug policy framework.

BackgroundMalaria remains a public health problem in Republic of the Congo. The sub-microscopic infection including gametocytaemia constitutes a parasite reservoir that is recognised to contribute to malaria transmission. It is known that primaquine, an 8-aminoquinoline, is effective to eliminate Plasmodium falciparum (Pf) gametocytes. However, it induces haemolytic anaemia in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd). It has been reported G6PDd also confers protection against severe malaria. To know the prevalence of G6PDd in the Congolese population is important in the case of future utilisation of this drug in the country. Therefore, in this study, we investigated 1) the prevalence of G6PDd in children infected with Pf and 2) the possible association between the presence of malaria, the presence of G6PD mutation and haemoglobin concentration.Methods229 children aged 1 to 10 years old presenting with fever (axillary T°≥37.5°C) were enrolled at the paediatric hospital Marien Ngouabi in Brazzaville. Thick and thin blood smears were done to detect and identify malaria parasites and determine parasite density. To detect the different glucose-6-phosphate dehydrogenase genotypes, a 968 bp fragment of the G6PD gene containing the polymorphisms 202G&gt1;A and 376&gt1;G was amplified by PCR followed by sequencing.ResultsMalaria prevalence was 22 (10%). With regard to G6PD analysis, it was found that 206 patients had G6PD genotype available including 74.8% (154/206) with G6PD normal, 12.1% (25/206) with heterozygous genotypes and 13.1% (27/206) with G6PD deficiency [11.6% (24/206) were male hemizygous and 1.4% (3/206) were female homozygous]. Data are further analysed to investigate the association between G6PD genotype, uncomplicated malaria, haemoglobin concentration as well as parasite densities.ConclusionA high prevalence of G6PD deficiency is reported for these Congolese children. Further investigation with larger sample size in different areas of the country is needed to design future and adapted interventions.