Endocrine Abstracts (2006) 11 P688

Identification and functional study of a new FSH receptor gene mutation in women affected by polycystic ovary syndrome (PCOS)

E Ferrarini1, F Jr Orio2, S Palomba3, T Cascella2, A Dimida1, S di Biase4, D Labella4, P Agretti1, G de Marco1, E Gianetti1, P Vitti1, A Colao2, G Lombardi2, E Pucci1, A Pinchera1 & M Tonacchera1

1Dipartimento di Endocrinologia, Centro di Eccellenza AmbiSEN, Pisa, Italy; 2Dipartimento di Endocrinologia ed Oncologia Molecolare e Clinica, Napoli, Italy; 3Dipartimento di Ginecologia ed Ostetricia, Catanzaro, Italy; 4Mergen, Laboratorio di Biologia Molecolare, Napoli, Italy.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases in women, affecting up to 10% of women in reproductive age. The evidence of polycystic ovaries at ultrasonography has been recently considered as a further criteria to diagnose PCOS. In order to determine whether FSH receptor gene affects hormonal and/or metabolic parameters of PCOS women the presence of FSH receptor gene mutations was investigated. Forthy women aged between 18 and 40 years with polycystic ovaries, body mass index (BMI) >25 kg/m2, testosterone >2.5 nmol/l, sex hormone binding globulin (SHBG) <30 nmol/l, oligoamenorrhea and/or hirsutism were included in this study. All of them had a normal development of secondary sexual characteristics and a normal karyotype (46,XX). Pelvic ultrasonography showed polycystic ovaries of abnormal size. After genomic DNA extraction from peripheral-blood lymphocytes of the women, exons 1–10 of the FSH receptor gene were amplified by PCR by specific primers, and directly sequenced. The genetic analysis showed a mutation of the FSHr in heterozygous state located in exon 10 of the receptor (T411D) in one patient. The parents had only wild-type sequence. The T411D mutation was not present in 30 normal subjects. The functional study of the identified FSHr mutation was performed. The mutated FSHr was obtained by site-directed mutagenesis. COS-7 cells transfected with the wild type FSHr (500 ngr/mL) and the mutated receptor (500 ngr/ml) were used to determine cAMP production after stimulation with increasing concentrations of hrFSH (1–5000 mU/mL) or hrCG (0,1–300.000 mU/mL). The T411D FSHr mutant did not show a different cAMP production in response to hrFSH stimulation with respect to the wtFSH. Very high concentrations of hCG were not able to stimulate cAMP production in COS-7 cells transfected with the mutated receptor.

In conclusion: we identified a FSHr mutation in a patient with PCOS. Transfection studies in eukaryotic cells did not show any modification of the functional properties of the mutated receptor with respect to the wild type.