Genetic factors determining predisposition to endometriosis and response to its treatment

The relative frequencies of the normal (+) and null (0) alleles of the glut athione-S-transferase M1 (GSTM1) gene, as well as those of the rapid (R) an d slow (S) forms of N-acetyl transferase 2 (NAT-2), were studied in the Rus sian and French populations and in endometriosis (EM) patients. In the tota l Russian and French populations, the proportions of homozygotes for deleti on in gene GstM1 (0/0) were 42.2 and 45.8%, respectively, whereas in Russia n and French EM patients, these values were 58.6 and 76.9%, respectively. T he differences in these proportions between the total population and subjec ts with EM were significant at the confidence levels of 0.98 (chi(2) = 5.45 ; P < 0.02) and 0.90 (chi(2) = 3.01; P < 0.1) for the French and Russian po pulations, respectively. The frequencies of allele S of the Nat-2 gene were also similar in the Russian and French populations (60 and 63.1%, respecti vely), with these frequencies being somewhat higher in EM patients (71.2 an d 77.7%, respectively). In Russians, the proportion of EM patients who were homozygous for the R form of NAT-2 (R/R) was significantly lower (chi(2) = 5.1). Forty-three of the patients with external genital EM received comple x treatment with the use of the interferon inducer Cyclopheron. In 17 patie nts, a pronounced positive dynamics was observed, and 29 patients exhibited an increased resistance to the immunomodulating therapy. These groups comp rised 1 and 25 GstM1 0/0 homozygotes, respectively; the number of patients with the slow NAT-2 form was 13 (7 S/S and 6 S/R genotypes) and 29 (20 S/S and 9 S/R genotypes), respectively. The obtained data indicate that the Gst M1 and Nat-2 genes are involved in EM pathogenesis. Therefore, molecular sc reening for the GstM1-0 and Nat-2-S alleles would be a good prognostic test when prescribing the postoperative treatment for EM and predicting its eff ectiveness.