Late-onset Adrenal Hypoplasia Congenita Research Articles

Identification and Analysis of a Novel NR0B1 Mutation in Late-Onset Adrenal Hypoplasia Congenita and Hypogonadism

ObjectiveX-linked adrenal hypoplasia congenita (AHC) is a rare disorder characterized by primary adrenal insufficiency and hypogonadotropic hypogonadism (HHG) caused by mutations of the NR0B1/DAX1 gene. We aimed to search for the presence of any NR0B1/DAX1 gene mutations in a referred patient and to further characterize the phenotypes of the identified mutation.Case PresentationHerein, we report a Japanese patient with a novel missense mutation of the NR0B1/DAX1 gene resulting in adult-onset AHC and HHG. The patient was referred with diffuse skin pigmentation at 28 years of age, presented partial adrenal insufficiency and had undiagnosed incomplete HHG. Urological examination revealed severe oligospermia and testicular microlithiasis.ResultsThe NR0B1/DAX1 gene mutation was identified by exome sequencing as a novel missense mutation (c.884A>T, p.Leu295His). We conducted in silico modeling of this mutant NR0B1/DAX1 protein (p.Leu295His) which affected the conserved hydrophobic core of the putative ligand-binding domain (LBD). In addition, functional analysis revealed that this mutant showed a decreased ability as a transcriptional repressor to suppress target genes, such as STAR and LHB. Furthermore, this mutant showed functionally impaired repression of steroidogenesis in human adrenocortical H295R cells.ConclusionsWe identified a novel missense mutation of the NR0B1/DAX1 gene in a patient suffering from late-onset AHC and HHG, who presented with oligospermia and testicular microlithiasis. This mutant NR0B1/DAX1 protein was found to have reduced repressor activity, according to in vitro studies, clinically consistent with the patient’s phenotypic features.

Late-onset adrenal hypoplasia congenita caused by a novel mutation of the DAX-1 gene

Late-onset adrenal hypoplasia congenita caused by a novel mutation of the DAX-1 gene

Late-onset adrenal hypoplasia congenita caused by a novel mutation of the DAX-1 gene

Mutation in the orphan nuclear receptor DAX-1 gene causes X-linked adrenal hypoplasia congenita (AHC). Affected male children classically suffer a salt-losing crisis and adrenal insufficiency in their early infancy or, in some rare exceptions, with late-onset subtype. We report here a patient manifesting late-onset adrenal hypoplasia congenita caused by the premature truncation of the C-terminus of the DAX-1 molecule, which is essential for its function as a transcriptional repressor. A 12-year-old boy was referred to us after being afflicted with generalized skin pigmentation for about 3 years, fatigue and headache. Primary adrenal insufficiency was determined on the basis of a low plasma cortisol level (3.9 microg/dl) despite an extremely high ACTH level (1200 pg/ml). Replacement therapy with hydrocortisone and fludorocortisone acetate was initiated soon thereafter. Hypogonadotropic hypogonadism was confirmed at the age of 18 years, at which time sexual infantilism had become apparent. Direct sequencing of the peripheral lymphocyte-derived DNA revealed a novel 1033del13 mutation on the ligand-binding domain of the NR0B1 (DAX-1) gene, which generated a premature stop codon truncating the C-terminus. This mutation was considered de novo since we could not find it in his mother. This case demonstrates that even a truncated protein lacking the major functional domain of DAX-1 can present late-onset and latent adrenal failure.