HNF1A gene mutations and premature ovarian failure (POF): evidence from a clinical paradigm combining MODY 3 and POF.

Premature ovarian failure (POF) defines the occurrence of ovarian failure prior to the age of 40. It occurs in one out of 100 women but is very rare before age 20 (1:10,000). Maturity-onset diabetes of the young (MODY), caused by mutations in the HNF1A gene, is also a rare disorder; all types of MODY account for 1-2% of adult diabetic cases. These two rare nosologic entities coexisted in an adolescent girl evaluated for delayed puberty. Although this combination could represent a chance association, an interrelation might exist. We examined HNF1A expression in human fetal and adult ovaries by immunohistochemistry using a polyclonal HNF1A antibody. HNF1A protein was expressed in both the fetal and adult human ovaries. Based on these findings, we hypothesize that HNF1A participates in ovarian organogenesis and/or function and that mutations in the HNF1A gene might represent another molecular defect causing POF, possibly in combination with other genetic factors. The study underlines the importance of rare clinical paradigms in leading the way to elucidation of the pathogenetic mechanisms of rare diseases.

CYP21A2 mutations in women with polycystic ovary syndrome (PCOS).

The question of the contribution of CYP21A2 heterozygosity to the development of polycystic ovary syndrome (PCOS) has repeatedly been raised in the literature. The available data, however, do not offer a satisfactory answer. The discrepancy must be attributed, primarily, to the small number of subjects in the various studies, the type of selected phenotype, and the number of searched mutations. The aim of the study was to define the contribution of CYP21A2 heterozygous mutations to the pathogenesis of PCOS. We searched for 14 molecular defects of the CYP21A2 gene in 197 PCOS women, employing allele specific PCR. Androgen levels were determined at baseline by appropriate methodology in the follicular phase. PCOS women with 17-hydroxyprogesterone (17OHP) basal values >2 ng/ml and/or post-ACTH >10 ng/ml were excluded. Appropriate controls were included. The frequency of the CYP21A2 heterozygous mutations in PCOS women and in controls was 7.6% and 5.9%, respectively [p-value (PCOS vs. controls): 0.663]. Homozygosity for CYP21A2 gene defects was not detected. In conclusion, the contribution of CYP21A2 heterozygous mutations to the pathogenesis of PCOS is not substantiated by our data. Moreover, 17-hydroxyprogesterone values of < 10 ng/ml post-ACTH exclude homozygosity of CYP21A2 mutations.