X-linked adrenal hypoplasia congenita (AHC) is rare disorder of adrenal gland development and associated with hypogonadotropic hypogonadism (HH). A　14-year-old boy was referred to our pediatric endocrinology clinic for recurrent hyponatremia. Physical examination revealed hyperpigmentation and prepubertal genitalia. Laboratory tests were compatible with a diagnosis of primary adrenal insufficiency and HH. The adrenal gland CT scan showed bilateral adrenal hypoplasia. Molecular investigation identified a novel mutation(c.833_835dup, p.Leu278dup) in the NROB1 gene. To our Knowledge, this mutation is novel and has not been reported. We hypothesize that the novel (p.Leu278dup) NROB1 mutation might be able to cause a distruption of NROB1 function and is probably involved in the development CAH and HH in this patient.