Table 2. GSTM1 and GSTP1 genotypes and minor allele frequencies in the study population.

Genetic variant	Homozygous for major allele N (%)	Heterozygous N (%)
GSTM1null *	73 (52.9)	-
GSTP1 313A>G	52 (37.7)	69 (50)
GSTP1 341C>T	117 (84.8)	18 (13)

Abbreviations: GSTM1: glutathione S transferase Mu1; GSTM1 null- homozygous individuals for deletion; GSTP1: glutathione S transferase Pi1. *Distinction cannot be made between GSTM1 non-null heterozygous and homozygous individuals by the method used in the study, therefore observed frequencies could not be provided. GSTM1 null individuals are considered as homozygous for major allele.