GLUTATHIONE-S-TRANSFERASE M1 GENE POLYMORPHISM AND SUSCEPTIBILITY TO ENDOMETRIOSIS IN A FRENCH POPULATION

Endometriosis is a multifactorial disease with possible genetic predis position and involvement of environmental factors in its pathogenesis. The genetic polymorphism of glutathione S-transferase M1 (GSTM1) gene , which codes for glutathione S-transferase 1, class mu foreign compou nd conjugating enzyme of phase II detoxification system, was studied b y polymerase chain reaction from the blood spots in patients with diff erent stages of endometriosis (n = 50) and in controls (n = 72) of Fre nch 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 genot ype), compared with 45.8% in a control group (P < 0.0001), which was c onsistent with the frequency of GSTM1 deletion in French population. M oreover, the distribution of GSTM1-active genotypes was significantly different in patients and controls (P < 0.0001), as no patient with GS TM1A/B genotype, which is correlated with the highest activity of GSTM 1 enzyme, has been found so far (18.1% in a control group). The unusua lly high frequency of homozygotes for the GSTM1 gene deletion among pa tients with endometriosis suggests a possible contribution of environm ental toxins in the pathogenesis of this disease due to the absence or low activity of GSTM1 enzyme.