title: X-linked adrenal hypoplasia congenita and hypogonadotropic hypogonadism: Identification and in vitro study of a novel small indel in the NR0B1 gene.
abstract: DAX1 is an orphan nuclear receptor that has a key role in the development and function of the adrenal and reproductive axes. Mutations in NR0B1, the gene encoding DAX1, result in X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HHG). A Chinese pedigree with X-linked AHC and HHG was investigated in the present study. Sequence analysis identified a novel small indel variant, c.195_207delinsTG, in the NR0B1 gene. To determine the effect of this variant on DAX1 expression, reverse‑transcription quantitative PCR and western blot assays were performed. The mRNA expression levels in carriers of mutant NR0B1 were significantly reduced (62% decrease) compared to those in individuals with wild-type NR0B1 (WT). The c.195_207delinsTG mutation was demonstrated to lead to various truncated DAX1 proteins, including the C‑terminal truncated DAX1, which was only detected in the cytoplasm, and the N‑terminal truncated DAX1, which was present in the cytoplasm and nucleus. A luciferase assay was then performed to assess the repressor function of DAX1 in modulating steroidogenic factor 1 (SF‑1)‑mediated transactivation. WT DAX1 significantly suppressed the SF‑1‑mediated promoter activity of the steroidogenic acute regulatory protein by 35.5±1.9%. In contrast to other known pathogenic mutations which abolish the repressor function of DAX1, the c.195_207delinsTG mutant proxkduced a higher repressor activity, demonstrating a 49.9±2.6% reduction of promoter activity. These findings suggested that the mutation of NR0B1 in X‑linked AHC with HHG enhanced the function of DAX1 to repress SF-1 activation, while DAX1 is expected to have additional roles in the pathological mechanism.
authors.affiliation: Department of Laboratory Medicine, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yu
authors.affiliation: Division of Birth Defects, Institute for Pediatric Translational Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, P.R. China.
authors.forename: Yongguo
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Internal Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Laboratory Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China.
authors.forename: Qihua
authors.initials: Q
authors.lastname: Fu
authors.affiliation: Department of Laboratory Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, P.R. China.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Laboratory Medicine, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, P.R. China.
authors.forename: Fuxiang
authors.initials: F
authors.lastname: Chen
mesh_terms: D000309:Adrenal Insufficiency / Q000235:genetics / Q000378:metabolism; D000328:Adult; D002460:Cell Line; D057137:DAX-1 Orphan Nuclear Receptor / Q000096:biosynthesis / Q000235:genetics; D005786:Gene Expression Regulation; D040181:Genetic Diseases, X-Linked / Q000235:genetics / Q000378:metabolism; D006801:Humans; D000075262:Hypoadrenocorticism, Familial; D054643:INDEL Mutation; D008297:Male; D054339:Steroidogenic Factor 1 / Q000235:genetics / Q000378:metabolism
chemical_list: D057137:DAX-1 Orphan Nuclear Receptor; C539965:NR0B1 protein, human; D054339:Steroidogenic Factor 1