Familial clustering in the polycystic ovarian syndrome.

To assess the degree of familial clustering and the mode of inheritance of the polycystic ovarian syndrome (PCO), the prevalence of PCO-related symptoms among first- and second-degree relatives of 132 PCO patients and 71 controls was studied using questionnaire data. 19.7% of male first-degree relatives of PCO patients were reported to have early baldness or excessive hairiness, as opposed to 6.5% of relatives of controls. For female first-degree relatives, the percentages for PCO-related symptoms were 31.4 and 3.2, respectively, in the two groups. In a subgroup of 52 families of PCO patients where one of the parents was reported to have symptoms, 35% of brothers and 58% of sisters had symptoms. Although autosomal dominant inheritance could be excluded as an explanation for PCO in the whole data set, the findings were consistent with this mode of inheritance for a sizeable fraction of families. X-linked dominant inheritance of PCO could be discarded.