Clinical and molecular characterization of five Spanish kindreds with X-linked adrenal hypoplasia congenita: atypical findings and a novel mutation in NR0B1.

BACKGROUND: X-linked adrenal hypoplasia congenita (AHC) is caused by NR0B1 (DAX1) gene mutations. Affected male children suffer from adrenal insufficiency, leading to a salt-wasting crisis in early infancy and hypogonadotropic hypogonadism in adulthood.

OBJECTIVE: To characterize clinically and at the molecular level a cohort of Spanish patients with AHC.

PATIENTS AND METHODS: Nine boys (from five families) with AHC were screened for NR0B1 mutations. Clinical and endocrine evaluations were recorded.

RESULTS: NR0B1 gene mutations were found in all analyzed patients, one of them being novel (p.Gln305*). One patient presented with preserved hypothalamic-pituitary-gonadal axis. Salt-wasting episodes, delayed puberty, and hypogonadotropic hypogonadism were common, although no association was observed between AHC phenotype and genetic mutations. None of the patients has had descendants.

CONCLUSIONS: AHC phenotype cannot be predicted based on genetic results as there is no definite genotype-phenotype relationship, including intrafamilial variability. Nevertheless, genetic testing for NR0B1 mutations is indicated if there is a suspicion of an X-linked adrenal insufficiency in order to proceed with the appropriate therapy and genetic counseling.