OBJETIVO: Determinar a frequência do polimorfismo +1730 G/A do gene do receptor beta de estrógeno (ERβ) em mulheres inférteis com e sem endometriose e controles. SUJEITOS E MÉTODOS: Estudo caso-controle que incluiu 136 mulheres com endometriose, 69 mulheres sem endometriose e 209 mulheres férteis como controles. O polimorfismo ERβ + 1730 G/A foi identificado por RFLP-PCR (Restriction Fragment Length Polymorphism - Polymerase Chain Reaction). RESULTADOS: Os genótipos GG, GA e AA do polimorfismo ERβ + 1730 G/A apresentaram frequência de 60,3%, 38,2% e 1,5%, respectivamente, nas mulheres com endometriose (p = 0,0022). Das mulheres inférteis sem endometriose, 63,8% apresentaram o genótipo homozigoto normal GG, 30,4% o genótipo heterozigoto GA e 5,8% o genótipo homozigoto mutado AA (p = 0,0275). No grupo controle, os genótipos GG, GA e AA apresentaram frequência de 77,5%, 21,1% e 1,4%. CONCLUSÃO: Os dados sugerem que o polimorfismo ERβ +1730G/ pode estar associado ao risco de infertilidade e infertilidade associada à endometriose.

OBJECTIVE: To determine the frequency of the estrogen receptor b gene (ERβ) +1730 G/A polymorphism in infertile women with and without endometriosis and controls. SUBJECTS AND METHODS: Case-control study that included 136 women with endometriosis, 69 women without endometriosis and 209 fertile women as controls. The ERβ gene + 1730 G/A polymorphism was identified by RFLP-PCR (Restriction Fragment Length Polymorphism - Polymerase Chain Reaction). RESULTS: Genotypes GG, GA and AA of the ERβ gene presented frequencies of 60.3%, 38.2% and 1.5%, respectively, in the women with endometriosis (p < 0.0022). Of the infertile women without endometriosis, 63.8% presented the normal homozygous genotype GG, 30.4% the GA heterozygous genotype, and 5.8% the homozygous mutated genotype AA (p < 0.0275). In the control group, 77.5% presented the normal homozygous genotype GG, 21.1% the heterozygous genotype GA, and 1.4% the homozygous mutated genotype AA. CONCLUSION: The data suggest that the estrogen receptor β gene (ERβ) +1730 G/A polymorphism can be associated with risk of infertility and endometriosis-associated infertility.