Absence of mutations in the coding regions of follicle-stimulating hormone receptor gene in Singapore Chinese women with premature ovarian failure and polycystic ovary syndrome

Screening of FSH receptor gene in Argentine women with premature ovarian failure (POF)

Diverse mutations in FSH-receptor (FSHR) gene have been described as possible cause of premature ovarian failure (POF). To investigate the presence of mutations and/or polymorphisms in FSHR gene, DNA from 20 POF, 5 of which were diagnosed as resistant ovary syndrome (ROS), and from 44 controls was isolated from peripheral lymphocytes. The complete coding sequence was analysed by PCR followed by SSCP, direct sequencing or restriction enzyme analysis. No mutations in FSHR gene were identified in the patients studied. The two already described polymorphisms in exon 10, A919G and A2039G, cosegregated in all the homozygous individuals, indicating that FSHR presents two isoforms: Ala307-Ser680 and Thr307-Asn680. OR results suggest that the 919G-2039G allelic variant or the homozygous genotype is not associated to disease risk. In addition, a heterozygous substitution T1022C (Val341Ala) was found in two control subjects. We suggest that mutations in FSHR gene are rare in women with POF in Argentine. Presence of a particular FSHR isoform does not appear to be associated with this disease.

Follicle-stimulating hormone receptor polymorphisms in women with normogonadotropic anovulatory infertility

OBJECTIVE

To assess the incidence of different FSH receptor genotypes in normogonadotropic anovulatory infertile women (World Health Organization class II) and normo-ovulatory controls and to correlate these genotypes with baseline characteristics and ovarian responsiveness during ovulation induction.

DESIGN

Cross-sectional study.

SETTING

University hospital.

PATIENT(S)

Thirty normo-ovulatory controls and 148 normogonadotropic anovulatory infertile women.

INTERVENTION(S)

All participants underwent a standardized evaluation that included cycle history, body mass index measurement, and transvaginal ultrasonography of ovaries. Fasting blood samples were obtained for endocrine evaluation. Ovarian responsiveness to FSH in normogonadotropic anovulatory infertile women was assessed during ovulation induction, and DNA was analyzed to determine the FSH receptor genotype.

MAIN OUTCOME MEASURE(S)

Prevalence of FSH receptor polymorphisms, baseline serum FSH levels, amount of FSH administered, duration of stimulation, and ovarian response dose.

RESULT(S)

The Thr/Thr 307 genotype was significantly less prevalent (52% vs. 23%) and the Ser/Ser 680 polymorphism was significantly more prevalent (40% vs. 16%) in patients compared with controls. Normogonadotropic anovulatory infertile women with the Ser/Ser 680 polymorphism presented with higher median FSH serum levels (5.2 IU/L [range, 2.4-9.7 IU/L]) than did those with the Asn/Asn 680 (4.6 IU/L [range, 1.4-5.8 IU/L) and Asn/Ser 680 (4.5 IU/L [range, 1.8-9.7 IU/L) variants. However, ovarian responsiveness to FSH was similar among anovulatory women with the various polymorphisms.

CONCLUSION(S)

Normogonadotropic anovulatory infertile patients have a different FSH receptor genotype than do normo-ovulatory controls. Although this characteristic is associated with increased baseline FSH serum levels, altered ovarian sensitivity to exogenous FSH during ovulation induction could not be established.

The polycystic ovary syndrome: what does insulin resistance have to do with it?

About half of infertility cases are attributable to female factors, of which anovulation is the leading cause. Most cases of anovulation are due to the polycystic ovarian syndrome (PCOS). Clinically PCOS, present in 5% of all women, consists of anovulation, acne, hirsutism, reversed LH-to-FSH ratio and often resistance to insulin. In some cases PCOS appears in familial clusters but its genetic cause is unknown. Several genes were suggested as possible culprits for PCOS but their involvement has not been proven. The central paradox regarding the role of insulin in PCOS is the high responsiveness to insulin by the ovary, as opposed to the resistance of the whole body. On the backdrop of knowledge of several paralogous genes for each of the participating proteins in the insulin signal transduction pathways, it is possible that different paralogues propagate the intracellular signal in the ovary as opposed to peripheral tissues. Studies by microarray techniques of the different gene expression profiles in the two ovarian cells and peripheral cells such as adipocytes could clarify whether the ovarian defect in PCOS is identical to the peripheral defect in insulin signal transduction, or whether serum insulin concentrations simply serve to reveal the ovarian defect.