Genetic Polymorphisms of Glucose-6-Phosphate Dehydrogenase in Lagos, Nigeria

Glucose-6-phosphate dehydrogenase (G6PD) is an essential enzyme in the pentose phosphate pathway that prevents oxidative damage to cells. This study determined the genotypic and allelic frequencies of G6PD G202A and A376G and also investigated correlation between G6PD polymorphisms and hemoglobin (Hb) phenotypes in children in Lagos, Nigeria. Seventy-eight children [55 with Hb AA (β^Α/β^A) and 23 with Hb AS (β^Α/β^S) trait] and 65 Hb SS (β^S/β^S) (HBB: c.20A>T) subjects in steady state with age range between 5-15 years were recruited for the study. Hemoglobin phenotypes of all study participants were carried out using alkaline electrophoresis and solubility tests. Genomic DNA was extracted from whole blood and restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) was used to determine the G202A and the A376G mutations of the G6PD gene. The genotype and allele distributions of G6PD G202A and A376G according to the Hb phenotypes were not statistically significant (p > 0.05). The minor allele frequency 202A was 0.15 (15.0%) and 0.14 (14.0%) in cases and controls, respectively. The overall frequency of 376G allele in the case group was 0.35 (35.0%) and 0.38 (38.0%) in the control group. No statistical significance was observed in the genotype and allele distributions of A376G in both the case and control groups (p > 0.05). The G6PD A- frequency in Hb SS subjects and the control group were 6.2 and 2.6%, respectively. G6PD G202A and A376G polymorphisms were not associated with Hb phenotypes and the allele distributions of 202A and 376G in this study are typical of West African populations.