A novel GNRHR gene mutation causing congenital hypogonadotrophic hypogonadism in a Brazilian kindred

Abstract

Congenital hypogonadotrophic hypogonadism (CHH) is a challenging inherited endocrine disorder characterised by absent or incomplete pubertal development and infertility as a result of the low action/secretion of the hypothalamic gonadotrophin‐releasing hormone (GnRH). Given a growing list of gene mutations accounting for CHH, the application of massively parallel sequencing comprises an excellent molecular diagnostic approach because it enables the simultaneous evaluation of many genes. The present study proposes the use of whole exome sequencing (WES) to identify causative and modifying mutations based on a phenotype‐genotype CHH analysis using an in‐house exome pipeline. Based on 44 known genes related to CHH in humans, we were able to identify a novel homozygous gonadotrophin‐releasing hormone receptor (GNRHR) p.Thr269Met mutant, which segregates with the CHH kindred and was predicted to be deleterious by in silico analysis. A functional study measuring intracellular inositol phosphate (IP) when stimulated with GnRH on COS‐7 cells confirmed that the p.Thr269Met GnRHR mutant performed greatly diminished IP accumulation relative to the transfected wild‐type GnRHR. Additionally, the proband carries three heterozygous variants in CCDC141 and one homozygous in SEMA3A gene, although their effects with respect to modifying the phenotype are uncertain. Because they do not segregate with reproductive phenotype in family members, we advocate they do not contribute to CHH oligogenicity. WES proved to be useful for CHH molecular diagnosis and reinforced its benefit with respect to identifying heterogeneous genetic disorders. Our findings expand the GnRHR mutation spectrum and phenotype‐genotype correlation in CHH.

A partial loss-of-function variant in GNRNR gene in a Chinese cohort with idiopathic hypogonadotropic hypogonadism

“…Moreover, serum FSH levels of Patient 2 and 3 were at the lower level of normal range, but the rest two patients did not showed that. Consistently, other studies also proved this phenotypic diversity in patients with GNRHR mutations, ranging from complete IHH to constitutional delay of puberty (7,12,21).…”

“…Due to deficiency of endogenous GNRHR expression, Simian virus 40 (SV40)-infected CV1 (COS-7) cells (African green monkey kidney fibroblast-like cell line, ATCC, CRL-1651) was chosen as cell model in our study (19)(20)(21). COS-7 cells were seeded at standard 6 well dishes and cultured with complete media (10% fetal bovine serum).…”

“…We treated transfected COS-7 cells with GnRH decapeptide (1 μM) for 1 h as previously described (21). Medium containing GnRH decapeptide was removed, and cells were washed three times with HBSS solution (HyClone, Shanghai, China).…”

Clinical and molecular features of 40 Chinese patients with idiopathic hypogonadotropic hypogonadism

“…Seminara et al ( 17 ) reported that one IHH patient carried KISS1R p.R331X and p.X399R mutations. The KISS1R mutation causes hypogonadism and delays puberty development in humans and mice, which can be improved by administering exogenous GnRH ( 18 ). Both brothers in Family III have nIHH disease, and the parents are consanguineous in marriage.…”