Polycystic Ovaries Are Inherited as an Autosomal Dominant Trait: Analysis of 29 Polycystic Ovary Syndrome and 10 Control Families

Abstract

The aim of this study was to obtain evidence for the genetic basis of polycystic ovaries (PCO) and premature male pattern baldness (PMPB) by screening first-degree relatives of women affected by polycystic ovary syndrome (PCOS). Because of the high prevalence of PCO in the general population, we also studied first-degree relatives of ten asymptomatic control volunteers of reproductive age. The probands were recruited prospectively from infertility and endocrine clinics, where they presented with various clinical symptoms of PCOS. Each had PCO, on transvaginal ultrasound scan. The families of 29 probands and 10 volunteers agreed to take part in the study. Clinical, ultrasound, and biochemical parameters were used to define PCO/PCOS. All female relatives had an ovarian ultrasound scan and hormone profile performed. History was used to assign status in postmenopausal women. All male relatives were assessed for early onset (<30 yr old) male pattern baldness, by photographs. All relatives were assigned affected (PCO/PMPB) or nonaffected status, and segregation analysis was performed. Of the relatives of 29 PCOS probands, 15 of 29 mothers (52%), 6 of 28 fathers (21%), 35 of 53 sisters (66%), and 4 of 18 brothers (22%) were assigned affected status. First-degree female relatives of affected individuals had a 61% chance of being affected. Of the first-degree male relatives, 22% were affected. Of a total of 71 siblings of PCOS probands, 39 were affected, giving a segregation ratio of 39/32 (55%), which is consistent with autosomal dominant inheritance for PCO/PMPB. In the control families, 1 of 10 probands (10%), 1 of 10 mothers (10%), no fathers, 2 of 13 sisters (15%), and 1 of 11 brothers (9%) were affected. Of a total of 24 siblings, 3 were affected (13%), giving a segregation ratio (observed/expected) of 3/12, which was significantly different from autosomal dominant inheritance. The inheritance of PCO and PMPB is consistent with an autosomal dominant inheritance pattern in PCOS families, perhaps caused by the same gene. There was no such genetic influence in families of women without PCOS. Sisters of PCOS probands with polycystic ovarian morphology were more likely to have menstrual irregularity and had larger ovaries and higher serum androstenedione and dehydroepiandrosterone-sulfate levels than sisters without PCO. This suggests a spectrum of clinical phenotype in PCOS families. Men with PMPB had higher serum testosterone than those without. Collectively, these data are consistent with a role for genetic differences in androgen synthesis, metabolism, or action in the pathogenesis of PCOS.