The remaining 3 probands with GNRHR mutations were from a subgroup of 18 patients without evidence of familial involvement, indicating a prevalence of 3 of 18 (16.7%) in patients with sporadic IHH and a normal sense of smell.
In order to describe the clinical features, genetic etiology, and treatment outcome of KS males with CLP, we performed genetic screening for 15 known causal IHH genes (KAL1, FGFR1, NELF, FGF8, CHD7, WDR11, SEMA3A, KISS1R, KISS1, PROKR2, PROK2, TAC3, TACR3, GNRH1, and GNRHR) in four KS with CLP patients and six IHH patients without CLP.
Deficiency in GnRH receptor trafficking due to a novel homozygous mutation causes idiopathic hypogonadotropic hypogonadism in three prepubertal siblings.
In addition, we found an even wider spectrum of reproductive function within pedigrees carrying an FGFR1 mutation ranging from IHH to delayed puberty to normal reproductive function (anosmia only or asymptomatic carriers).
Although mutations in the fibroblast growth factor receptor 1 (FGFR1) gene have been implicated in the development of IHH, KS, and SOD, the relevance of FGFR1 abnormalities to CPHD remains to be elucidated.
FGFR1 mutations cause isolated hypogonadotropic hypogonadism (IHH) with or without olfactory abnormalities, Kallmann syndrome, and normosmic IHH respectively.
Comparative functional analysis of two fibroblast growth factor receptor 1 (FGFR1) mutations affecting the same residue (R254W and R254Q) in isolated hypogonadotropic hypogonadism (IHH).
To address this issue, we studied 2 families, one with Kallmann syndrome (IHH and anosmia) and another with normosmic IHH, in which a single-gene defect had been identified: a heterozygous FGF receptor 1 (FGFR1) mutation in pedigree 1 and a compound heterozygous gonadotropin-releasing hormone receptor (GNRHR) mutation in pedigree 2, both of which varied markedly in expressivity within and across families.
These results support the hypothesis that IHH/KS patients with digenic mutations in Fgfr1/Fgf8 may have a further reduction in the GnRH neuronal population compared to patients harbouring monogenic haploid mutations in Fgfr1 or Fgf8.
The purpose of this study was to determine whether FGFR1 mutations were present in a unique family with autosomal dominant, fully penetrant, normosmic IHH.
KS is a genetically heterogeneous disorder consisting of idiopathic hypogonadotropic hypogonadism (IHH) and anosmia, and is most commonly due to KAL1 or FGFR1 mutations.
To describe a mother with idiopathic hypogonadotropic hypogonadism (IHH) and her monozygotic (MZ) twin boys who all have the same heterozygous fibroblast growth factor receptor-1 (FGFR1) gene mutation.
Ours is the first report of normosmic IHH associated with a mutation in the alternatively spliced exon 8A and suggests that this disorder can be caused by defects in either of the two alternatively spliced FGFR1 isoforms.
Six novel mutations (p.154_158del, p.E496Rfs*12, p.W190X, p.S134D, p.W10X, and c.1552 + 3insT) in FGFR1, two novel mutations (p.E176K and p.R184C) in FGF8, three novel mutations (p.48_52del, p.P120L, and p.K191R) in FGF17, and five reported mutations (p.W289X, p.G237S, p.V102I, p.R250Q, and p.T340M) in FGFR1 were identified in 18 IHH patients.
Nine nIHH subjects (five males and four females; 7%) harbor a heterozygous mutation in FGFR1 and exhibit a wide spectrum of pubertal development, ranging from absent puberty to reversal of IHH in both sexes.All mutations impair receptor function.
More recently, mutations in TAC3 and TACR3 genes, which encode neurokinin B and its receptor, have been implicated in normosmic IHH, although their precise functions in reproduction remain unclear.