Presence of metabolic risk factors in non-obese PCOS sisters: evidence of heritability of insulin resistance.

This study was performed to determine whether phenotypically healthy sisters of women with polycystic ovary syndrome (PCOS) have evidence of insulin resistance. We studied 54 women: 17 with PCOS, 17 sisters of these probands and 20 control women with similar age, body mass index (BMI) and waist-to-hip ratio (WHR). The PCOS sisters had neither clinical nor laboratory evidence of hyperandrogenism. However, estimated insulin resistance indices indicated decreased insulin sensitivity in PCOS sisters compared with the controls. No difference of insulin resistance indices was detected between the PCOS and their sisters. This finding provides additional evidence that there is a hereditary trait regarding insulin resistance in the PCOS families.