Abstract

The Mu (μ) and Theta (Θ) classes of glutathione transferase gene, GSTM1 and GSTT1 are polymorphic in humans. GSTM1 and GSTT1 enzyme deficiencies have been suggested to predispose people to lung, bladder and colorectal cancer. This study was carried out to investigate the distribution of Glutathione transferases (GSTs) genotype frequency in the three major Nigerian ethnic groups with a view to understanding the implication of the GST polymorphisms on disease susceptibility. Three hundred unrelated volunteers from the three major Nigerian ethnic groups of Hausa, Ibo and Yoruba who consented to the study were genotyped for GSTM1*1, GSTM1*0, GSTT1*1 and GSTT1*0 by polymerase chain reaction (PCR) technique. The homozygous null GSTM1*0 genotype frequency was found to be 37% in Hausa, 23% in Ibo and 31% in Yoruba with significant difference (p<0.05) especially, in the Ibo ethnic group while GSTT1*0 genotype was found at a comparably high frequencies of 42, 36, and 35% in the Hausa, Ibo and Yoruba populations of Nigeria, respectively. The genotype frequencies of the null GSTM1 and GSTT1 were found to be relatively high in the Nigerian population with a possible implication on increase susceptibility to some cancers.

Key words: Genetic polymorphisms, genotyping, Nigerian populations, Glutathione-S-transferases.