RESUMO
<p><b>OBJECTIVE</b>To study the relationship between estrogen receptor beta gene (ER beta) polymorphism and unknown aetiology hypomenorrhea in Southwestern China .</p><p><b>METHODS</b>One hundred eumenorrhea women were chosen as control group and another 100 hypomenorrhea patients as case group from Southwestern China. Restriction fragment length polymorphism (RFLP) of the Rsa I and Alu I in ER beta gene was analysed. The ER beta gene polymorphism genotype distribution in case group and control group was compared.</p><p><b>RESULTS</b>R allele frequency in case and control groups was 37.5% and 48.5% respectively, the OR was 0.64 (95%CI: 0.42-0.97), P= 0.026. A allele frequency in case and control groups was 18.0% and 11.5% respectively, the OR was 1.69 (95%CI: 0.93-3.09), P= 0.07. RFLP of Rsa I and Alu I in both groups were distributed with polymorphism.</p><p><b>CONCLUSION</b>ERbeta gene polymorphism has a relation with unknown aetiological hypomenorrhea. R allele may be the guard factor, and A allele may be its risk factor.</p>