+1730 G/A polymorphism of the estrogen receptor beta gene (ERbeta) may be an important genetic factor predisposing to endometriosis.

OBJECTIVE

To determine the frequency of the estrogen receptor gene (ERbeta) +1730 G/A polymorphism in Brazilian women with endometriosis.

DESIGN

Case-control study.

SETTING

Endometriosis Outpatient Clinic and Family Planning Outpatient Clinic of ABC Faculty of Medicine.

POPULATION

A total of 108 patients with endometriosis and a control group consisting of 210 fertile women.

METHODS

The ERbeta gene +1730 G/A polymorphism was identified by restriction fragment length polymorphism-polymerase chain reaction.

MAIN OUTCOME MEASURE(S): Genotype distribution and allele frequency of the +1730 G/A polymorphism in the ERbeta gene.

RESULTS

Genotypes GG, GA and AA of the ERbeta gene presented frequencies of 50.9%, 47.2% and 1.9%, respectively, in the women with endometriosis. Among the patients with stage I/II endometriosis, 47% presented the normal homozygous genotype GG; 51% had a GA heterozygous genotype and 2% had a homozygous mutated genotype AA. Among the patients with stage III/IV endometriosis, genotypes GG, GA and AA were present in 54.3%, 44% and 1.7%, respectively. In the control group, 74.3% presented the normal homozygous genotype GG, 24.3% the heterozygous genotype GA and 1.4% the homozygous mutated genotype AA.

CONCLUSION

The data suggest that the ERbeta gene +1730 G/A polymorphism can be associated with the risk of endometriosis development, regardless of the stage of the disease.