Intrauterine Environment in Polycystic Ovary Syndrome (PCOS) Probands

BACKGROUND Polycystic ovary syndrome (PCOS) is among the most common endocrine disorders in premenopausal women, affecting 7-10% of this population. This syndrome is characterized by hyperandrogenism, chronic anovulation and, frequently, obesity. Hyperandrogenemia seems to be a consistent reproductive phenotype in male relatives as well as female relatives of PCOS women. This phenotype appears to have a genetic basis in PCOS families and shows significant linkage and association with a marker locus on chromosome 19p in the region of the insulin receptor (allele 8 of D19S884.). This allele is also recently found to be associated with a metabolic phenotype in PCOS probands and their brothers, including increased post-challenge glucose levels, apparent defects in insulin secretion, especially in response to sulfonylurea, and accelerated weight gain with age (unpublished date). Therefore, allele 8 status in PCOS probands and their family members can identify the reproductive and metabolic abnormalities.

Many epidemiologic studies showed a plausible link between low birth weight and chronic metabolic disorders manifested as hypertension, diabetes and obesity later in life, suggestive of an early fetal programming. There is evidence to support fetal origin of PCOS. Female rhesus monkeys that were exposed to excess androgen in utero, were born smaller for gestational age. These animals had many of the reproductive features of PCOS, including increased LH levels, irregular ovulation, polycystic ovaries and functional ovarian hyperandrogenism. Similarly, in retrospective cohort studies, girls with elevated adrenal androgen levels or with PCOS were significantly smaller for gestational age at birth than reproductively normal control girls, suggestive of a possible fetal origin for some features of PCOS in human studies. Molecular mechanism for fetal programming is not clearly understood, but permanent changes in gene expression caused early insult may be a factor.

HYPOTHESIS These observations have led to a new hypothesis for the etiology of PCOS; genetic variation resulting in hyperandrogenemia leads to many of the reproductive and metabolic features of PCOS later in life. We will directly test the hypothesis that there is an excess androgen production in female offspring of women with PCOS. Further, we will test whether A8(+) female offspring have more profound changes in these parameters (increased androgen and/or decreased insulin levels in fetal life and in infancy) compared to A8(-) female offspring.