Laboratory of Molecular and Translational Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
Molecular Biology and Lysosomal Disease Diagnosis Laboratory, Department of Biophysics, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
J Neuroendocrinol. 2018 Dec;30(12):e12658. doi: 10.1111/jne.12658. Epub 2018 Dec 19.
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.
先天性低促性腺激素性性腺功能减退症（CHH）是一种具有挑战性的遗传性内分泌疾病，其特征是由于下丘脑促性腺激素释放激素（GnRH）的作用/分泌低下，青春期发育不全和不育。鉴于越来越多的基因突变导致 CHH，大规模平行测序的应用构成了一种出色的分子诊断方法，因为它可以同时评估许多基因。本研究提出使用全外显子组测序（WES）根据使用内部外显子组管道的表型-基因型 CHH 分析来鉴定致病和修饰突变。基于与人类 CHH 相关的 44 个已知基因，我们能够鉴定出一种新的纯合促性腺激素释放激素受体（GNRHR）p.Thr269Met 突变体，该突变体与 CHH 家系一起分离，并通过计算机分析预测为有害。一项功能研究测量了 COS-7 细胞中 GnRH 刺激时的细胞内肌醇磷酸盐（IP），证实 p.Thr269Met GnRHR 突变体相对于转染的野生型 GnRHR 的 IP 积累大大减少。此外，先证者携带 CCDC141 中的三个杂合变体和 SEMA3A 基因中的一个纯合变体，但它们对修饰表型的影响尚不确定。由于它们与家庭成员的生殖表型不分离，我们认为它们不会导致 CHH 多基因性。WES 被证明对 CHH 分子诊断有用，并在识别异质性遗传疾病方面增强了其益处。我们的发现扩展了 GnRHR 突变谱和 CHH 中的表型-基因型相关性。
