Molecular Human Reproduction vol.3 no.9 pp. 775–780, 1997 Glutathione S-transferase M1 gene polymorphism and susceptibility to endometriosis in a French population

5To whom correspondence should be addressed Endometriosis is a multifactorial disease with possible genetic predisposition and involvement of environ-mental factors in its pathogenesis. The genetic polymorphism of glutathione S-transferase M1 (GSTM1) gene, which codes for glutathione S-transferase 1, class µ foreign compound conjugating enzyme of phase II detoxification system, was studied by polymerase chain reaction from the blood spots in patients with different stages of endometriosis (n J 50) and in controls (n J 72) of French origin. A total of 86.0 % of patients appeared to lack GSTM1 enzyme activity due to the presence of an extended deletion (GSTM1 0/0 genotype), compared with 45.8 % in a control group (P < 0.0001), which was consistent with the frequency of GSTM1 deletion in French population. Moreover, the distribution of GSTM1-active genotypes was significantly different in patients and controls (P < 0.0001), as no patient with GSTM1A/B genotype, which is correlated with the highest activity of GSTM1 enzyme, has been found so far (18.1 % in a control group). The unusually high frequency of homozygotes for the GSTM1 gene deletion among patients with endometriosis suggests a possible contribution of environmental toxins in the pathogenesis of this disease due to the absence or low activity of GSTM1 enzyme. Key words: detoxification/endometriosis/genetics/glutathione S-transferase