OBJECTIVE: We inversigated Small Heterodimer Partner (SHP) gene mutation in Korean Polycystic Ovarian Syndrome (PCOS) patients. SHP protein regulates the activity of nuclear receptors which regulate the cellular development and differentiation. Recently, the mutation of SHP gene was found in the obesity and diabetes patients in Japanese group, and suggested that its mutation may involved in pathogenic mechanism of PCOS. METHODS: This study was performed in 20 PCOS patients and 20 normal women. The DNAs were extracted from the peripheral bloods, and amplified at each exon (1 and 2) of SHP gene by PCR method. Subsequently, each PCR product was digested with the restriction enzyme indicated below for studying restriction fragment length polymorphism (RFLP). After enzyme digestion, the results of RFLP were compared PCOS patients with control women to find any sequence variation. RESULTS: We examined 9 regions of exon 1 with Msp I, Pvu II, Dde I and 3 regions of exon 2 with Pst I, Dde I. There is no heterozygous or homozygous mutation in patients and control women at these restriction sites. CONCLUSION: The genetic analysis at our restriction sites in the SHP gene did not show any genetic variation in Korean PCOS patients. Our PCR-RFLP analysis was not covered the entire SHP gene (68 bp/ 1,006 bp), we need to further analysis of the entire SHP gene.