CASE REPORT A new FSHb mutation in a 29-year-old woman with primary amenorrhea and isolated FSH deficiency: functional characterization and ovarian response to human recombinant FSH Marie-Laure Kottler, Yen-Yin Chou 2,3 , Olivier Chabre 1 , Nicolas Richard, Camille Polge 1 , Sylvie Brailly-Tabard 4,5,7 , Philippe Chanson 4,5,6 , Anne Guiochon-Mantel 4,5,7 , Ilpo Huhtaniemi 2 and Jacques Young 4,5,6 Unite ´ de Formation et de Recherche de Me ´decine Centre Hospitalier Universitaire, De ´partement Ge ´ne ´tique et Reproduction, Universite ´ de Caen Basse-Normandie, F-14032 Caen, France, 1 Service d’Endocrinologie, Universite ´ et CHU Grenoble, Grenoble, F-38000 France, 2 Department of Reproductive Biology, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK, 3 Institute of Clinical Medicine, National Cheng Kung University Medical College and Hospital, Tainan, Taiwan, ROC, 4 Faculte ´ de Me ´decine Paris-Sud, Universite ´ Paris-Sud 11, Le Kremlin Bice ˆtre F-94276, France, 5 INSERM UMR-S693, Le Kremlin Bice ˆtre F-94276, France, 6 Assistance Publique-Ho ˆpitaux de Paris, Ho ˆpital de Bice ˆtre, Service d’Endocrinologie et des Maladies de la Reproduction, 78, Rue du Ge ´ne ´ral Leclerc, Le Kremlin Bice ˆtre F-94275, France and 7 Laboratoire de Ge ´ne ´tique Mole ´culaire, Pharmacoge ´ne ´tique et Hormonologie, Le Kremlin Bice ˆtre F-94275, France (Correspondence should be addressed to J Young at Assistance Publique-Ho ˆpitaux de Paris, Ho ˆpital de Bice ˆtre, Service d’Endocrinologie et des Maladies de la Reproduction; Email: jacques.young@bct.aphp.fr) (M-L Kottler and Y-YChou contributed equally to this work; I Huhtaniemi and J Young contributed equally to this work) Abstract Context: Mutations of the FSHb gene, causing in women isolated FSH deficiency and hypogonadism, are very rare and only a few have been described. Objective: To describe the phenotype and response to recombinant human (rh) FSH of a female patient with a novel homozygous loss-of-function mutation of FSHb, and to characterize in vitro the molecular mechanisms responsible for the FSH inactivation. Patient: A 29-year-old woman with primary amenorrhea and impaired pubertal development associated with isolated FSH deficiency. Methods and results: Sequencing of the FSHb gene revealed a homozygous 1 bp (G) deletion at codon 79 (c.289delG) of exon 3 which produced a frameshift at codon 79 (A79fs108X) and a premature stop codon at codon 109. The wild-type and mutant FSHb cDNAs inserted into expression vector were cotransfected into Chinese hamster ovary cells with the a-subunit. Wild-type FSH was readily detectable in culture medium, whereas no mutant FSH was detectable by either immunoassay or in vitro bioassay. Mutant FSHb protein could not be detected in western blot. In response to a 15-day treatment with rhFSH, sonography revealed multifollicular development in the ovaries. Circulating levels of estradiol and inhibin B were dramatically increased, whereas anti- Mullerian hormone decreased. Serum LH first decreased and then increased, inducing multiovulation associated with supraphysiologic progesterone and inhibin A levels. Conclusion: A novel FSHb mutation was detected in a hypogonadal woman. rhFSH was effective in ovulation induction in the patient but with signs of ovarian hyperstimulation. The high pretreatment LH levels could contribute to this excessive ovarian response to rhFSH. European Journal of Endocrinology 162 633–641 Introduction The pituitary gonadotropins, LH and FSH regulate the production of sex steroids necessary for the pubertal development and fertility. Inherited genetic defects that cause hypogonadism in females have been identified at multiple levels of the hypothalamic–pituitary–gonadal axis, including GnRH, its receptor, GPR54/KISS1R, TAC3/TACR3, gonadotropin subunits, genes involved in autosomal Kallmann syndrome and CHARGE syndrome, and gonadotropin receptors (1–17). Inacti- vating mutations in the FSHb gene have been found to date in five women with delayed puberty and isolated FSH deficiency (8, 10, 11, 16–19). These very rare natural mutations in the FSHb subunit gene are nevertheless interesting models to elucidate several aspects of the gonadotropin-dependent ovarian physi- ologyand physiopathology. In this study, we report and characterize in vitro a novel FSHb mutation and demonstrate that the mutant FSHb displays impaired European Journal of Endocrinology (2010) 162 633–641 ISSN 0804-4643 q 2010 European Society of Endocrinology DOI: 10.1530/EJE-09-0648 Online version via www.eje-online.org Downloaded from Bioscientifica.com at 06/08/2020 02:18:28AM via free access