Endometriosis is a chronic disease caused by the presence of endometrial tissue in ectopic locations outside the uterus. Chronic exposure to the environmental pollutant dioxin has been correlated with an increased incidence in the development of endometriosis in non-human primates. We have therefore examined whether there is an association between the polymorphisms of ten dioxin detoxification genes and endometriosis in Japanese women.

This was a pilot study in which 100 patients with endometriosis and 143 controls were enrolled. The prevalence of five microsatellite and 28 single nucleotide polymorphism markers within ten dioxin detoxification genes ( AhR , AHRR , ARNT , CYP1A1 , CYP2E1 , EPHX1 , GSTM1 , GSTP1 , GSTT1 , NAT2 ) was examined.

Taking into account that this analysis was a preliminary study due to its small sample size and genetic power, the results did not show any statistically significant difference between the cases and controls for any of the allele and genotype frequency distributions examined. In addition, no significant associations between the allele/genotype of all polymorphisms and the stage (I–II or III–IV) of endometriosis were observed.

Based on the findings of this pilot study, we conclude the polymorphisms of the ten dioxin detoxification genes analyzed did not contribute to the etiology of endometriosis among our patients.