Clinical spectrum and molecular basis in 19 Chinese patients with 46, XY disorder of sexual development caused by NR5A1 mutations

Abstract Background Nuclear receptor subfamily 5 group A member 1 (NR5A1) plays pivotal roles in steroidogenesis and gonadal development. 46, XY disorder of sexual development (DSD) caused by NR5A1 mutations is a rare genetic condition. This study aimed to provide a comprehensive analysis of the clinical characteristics and molecular defects observed in 19 Chinese patients with NR5A1 variants, including assessing the deleterious effects of novel variants in vitro and evaluating their functional impact on the gonad and adrenal glands in vivo. Materials and methods Subjects with NR5A1 variants were identified from 223 Chinese 46, XY DSD patients via next-generation sequencing. In-silico analysis and functional assays were performed to evaluate the transcriptional activity, expression levels and nuclear localization of novel NR5A1 variants. The histological structure of the gonads was evaluated via immunohistochemistry (IHC). Results Patients with NR5A1 gene variants presented with serious conditions, including micropenis, cryptorchidism, azoospermia, and radiological abnormalities of the spleen. Five novel NR5A1 variants were identified, including heterozygous p.Y5*, p.Q42E and p.L359_L363del, as well as copy number variation (CNV) of chr9:127213317–127570245_del and an exon 6 duplication. A total of 63.2% (12/19) of patients harbored additional variants other than NR5A1. Defective transcriptional regulatory activities and abnormal protein expression levels were observed in NR5A1 variants. The reduced levels of DHEA-S and 11-oxygenated steroids indicate a mild impairment in adrenal function among certain patients. The IHC analysis of the testis revealed intact expression levels of SOX9 in Sertoli cells, while significant differences were observed in the expression pattern of CYP17A1 in Leydig cells among patients. The preserved maturation of adult Leydig cells in the patients may trigger spontaneous puberty. Conclusions Patients with NR5A1 mutations exhibit complex phenotypes. The observed clinical heterogeneity may be attributed to oligogenic mutations, dysregulated Leydig cell function, as well as the impaired ability to modulate the transcription of target genes.