title: Non-syndromic congenital hypogonadotropic hypogonadism: clinical presentation and genotype-phenotype relationships.
abstract: Congenital hypogonadotropic hypogonadism (CHH) results from abnormal gonadotropin secretion, and it is characterized by impaired pubertal development. CHH is caused by defective GNRH release, or by a gonadotrope cell dysfunction in the pituitary. Identification of genetic abnormalities related to CHH has provided major insights into the pathways critical for the development, maturation, and function of the reproductive axis. Mutations in five genes have been found specifically in Kallmann's syndrome, a disorder in which CHH is related to abnormal GNRH neuron ontogenesis and is associated with anosmia or hyposmia. In combined pituitary hormone deficiency or in complex syndromic CHH in which gonadotropin deficiency is either incidental or only one aspect of a more complex endocrine disorder or a non-endocrine disorder, other mutations affecting GNRH and/or gonadotropin secretion have been reported. Often, the CHH phenotype is tightly linked to an isolated deficiency of gonadotropin secretion. These patients, who have no associated signs or hormone deficiencies independent of the deficiency in gonadotropin and sex steroids, have isolated CHH. In some familial cases, they are due to genetic alterations affecting GNRH secretion (mutations in GNRH1, GPR54/KISS1R and TAC3 and TACR3) or the GNRH sensitivity of the gonadotropic cells (GNRHR). A minority of patients with Kallmann's syndrome or a syndromic form of CHH may also appear to have isolated CHH, but close clinical, familial, and genetic studies can reorient the diagnosis, which is important for genetic counseling in the context of assisted reproductive medicine. This review focuses on published cases of isolated CHH, its clinical and endocrine features, genetic causes, and genotype-phenotype relationships.
authors.affiliation: Université Paris-Sud 11 and INSERM U 693, Faculté de Médecine Paris Sud, Le Kremlin Bicêtre, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Brioude
authors.forename: Jérôme
authors.initials: J
authors.lastname: Bouligand
authors.forename: Séverine
authors.initials: S
authors.lastname: Trabado
authors.forename: Bruno
authors.initials: B
authors.lastname: Francou
authors.forename: Sylvie
authors.initials: S
authors.lastname: Salenave
authors.forename: Peter
authors.initials: P
authors.lastname: Kamenicky
authors.forename: Sylvie
authors.initials: S
authors.lastname: Brailly-Tabard
authors.forename: Philippe
authors.initials: P
authors.lastname: Chanson
authors.forename: Anne
authors.initials: A
authors.lastname: Guiochon-Mantel
authors.forename: Jacques
authors.initials: J
authors.lastname: Young
mesh_terms: D000293:Adolescent; D000328:Adult; D000568:Amenorrhea / Q000209:etiology; D005260:Female; D005838:Genotype; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics; D006801:Humans; D007006:Hypogonadism / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D007223:Infant; D017436:Kallmann Syndrome / Q000235:genetics / Q000503:physiopathology; D008297:Male; D015287:Neurokinin B / Q000235:genetics; D010641:Phenotype; D011498:Protein Precursors / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000235:genetics; D000074502:Receptors, Kisspeptin-1; D011966:Receptors, LHRH / Q000235:genetics; D018042:Receptors, Neurokinin-3 / Q000235:genetics; D013739:Testosterone / Q000097:blood
chemical_list: C118688:KISS1R protein, human; D011498:Protein Precursors; D043562:Receptors, G-Protein-Coupled; D000074502:Receptors, Kisspeptin-1; D011966:Receptors, LHRH; D018042:Receptors, Neurokinin-3; C050866:progonadoliberin I; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D015287:Neurokinin B