Gitelman disease associated with growth hormone deficiency, disturbances in vasopressin secretion and empty sella: A new hereditary renal tubular-pituitary syndrome?

Gitelman disease was diagnosed in two unrelated children with hypokalemic m etabolic alkalosis and growth failure (a boy and a girl aged 7 mo and 9.5 y , respectively, at clinical presentation) on the basis of mutations detecte d in the gene encoding the thiazide-sensitive NaCl cotransporter of the dis tal convoluted tubule. GH deficiency was demonstrated by specific diagnosti c tests in both children Hypertonic saline infusion tests showed a partial vasopressin deficiency in the girl and delayed secretion of this hormone in the boy. Magnetic resonance imaging revealed an empty sella in both cases. Up to now, hypomagnesemia and hypocalciuria have been considered obligator y criteria for the diagnosis of Gitelman disease; however, our two patients had hypomagnesemia and hypocalciuria in less than half the determinations. GH replacement treatment was associated with a good clinical response in b oth children. It appears that these cases represent a new phenotype, not pr eviously described in Gitelman disease, and that the entity may be consider ed a new complex hereditary renal tubular-pituitary syndrome.