Our purpose was to identify, within the Taiwanese population of PCOS, the prevalence of the IRS-1 gene mutation with impaired tyrosine kinase activity, in order toassess whether the identity of the IRS-1 gene mutation of codon 513 (GCC->CCC) and codon 972 (GGG->AGG) can act as an appropriate diagnostic indicator for Taiwanese PCOS characterized by hyperinsulinemia and hyperandrogenism. The gene discussed is IRS1; the disease is hyperandrogenism.