| Disease ID | Source | Name | Description |
| 615271 | OMIM | Hypogonadotropic hypogonadism 21 with or without anosmia (HH21) | A disorder characterized by absent or incomplete sexual maturation by the age of 18 years, in conjunction with low levels of circulating gonadotropins and testosterone and no other abnormalities of the hypothalamic-pituitary axis. In some cases, it is associated with non-reproductive phenotypes, such as anosmia, cleft palate, and sensorineural hearing loss. Anosmia or hyposmia is related to the absence or hypoplasia of the olfactory bulbs and tracts. Hypogonadism is due to deficiency in gonadotropin-releasing hormone and probably results from a failure of embryonic migration of gonadotropin-releasing hormone-synthesizing neurons. In the presence of anosmia, idiopathic hypogonadotropic hypogonadism is referred to as Kallmann syndrome, whereas in the presence of a normal sense of smell, it has been termed normosmic idiopathic hypogonadotropic hypogonadism (nIHH). The disease is caused by variants affecting distinct genetic loci, including the gene represented in this entry. Some patients carrying mutations in FLRT3 also have a mutation in another HH-associated gene including FGFR1, HS6ST1 and FGF17 (PubMed:23643382). |