Inappropriate tall stature and renal ectopy in a male patient with X-linked congenital adrenal hypoplasia due to a novel missense mutation in theDAX-1 gene

Hypogonadotropic hypogonadism in subjects with DAX1 mutations

DAX1 (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1; also known as NROB1, nuclear receptor subfamily 0, group B, member 1) encodes a nuclear receptor that is expressed in embryonic stem (ES) cells, steroidogenic tissues (gonads, adrenals), the ventromedial hypothalamus (VMH), and pituitary gonadotropes. Humans with DAX1 mutations develop an X-linked syndrome referred to as adrenal hypoplasia congenita (AHC). These boys typically present in infancy with adrenal failure but later fail to undergo puberty because of hypogonadotropic hypogonadism (HHG). The adrenal failure reflects a developmental abnormality in the transition of the fetal to adult zone, resulting in glucocorticoid and mineralocorticoid deficiency. The etiology of HHG involves a combined and variable deficiency of hypothalamic GnRH secretion and/or pituitary responsiveness to GnRH resulting in low LH, FSH and testosterone. Treatment with exogenous gonadotropins generally does not induce spermatogenesis. Animal models indicate that DAX1 also plays a critical role in testis development and function. As a nuclear receptor, DAX1 has been shown to function as a transcriptional repressor, particularly of pathways regulated by other nuclear receptors, such as steroidogenic factor 1 (SF1). In addition to reproductive tissues, DAX1 is also expressed at high levels in ES cells and plays a role in the maintenance of pluripotentiality. Here we review the clinical manifestations associated with DAX1 mutations as well as the evolving information about its function based on animal models and in vitro studies.

[Gene as a cause of adrenal hypoplasia, hypogonadism and short height novel mutation of DAX-1 gene (pGly168fsX17)]

Various genes play a role in the morphogenesis of the adrenal cortex, among them the DAX-1 gene. We report an 18-year-old man who showed complete adrenal failure in the neonatal period, hypogonadotropic hypogonadism and pathological short stature associated with a mutation of the DAX-1 gene that has not previously been described. The patient was admitted to hospital at the age of 16 days due to salt-losing syndrome with hyperpotassemia. After this episode, he received no treatment for 2 years, when he began to show progressive anorexia, salt avidity, asthenia, cutaneous hyperpigmentation and finally shock, with hypoglycemia, hyponatremia, metabolic acidosis and hyperpotassemia. Puberal development was spontaneous but incomplete. The patient received treatment with testosterone-depot. He reached a definitive testicular volume of 6 ml and pubarche V. His final height is 150 cm (target height 164 cm). Amplification of the DAX-1 gene showed mutation g 2080-2081 insertion in the first position of codon 168, which produces a premature shutdown of protein DAX-1 at position 184.