Bartter’s syndrome type 5; a case report

Abstract

Bartter’s syndrome is a heterogeneous rare disease occurring due to deficiency in sodium and chloride absorption. Biochemical profile is hypokalemic metabolic alkalosis, renal salt wasting, elevated renin and aldosterone levels with normal or low blood pressure. In some individuals, hypercalciuria is also present. Mutations in several genes have been associated with the disorder. Gain of function mutations in the calcium-sensing receptor (CaSR) has been described in some patients with Bartter’s syndrome associated to hypocalcemia and hypercalciuria (Bartter’s syndrome type 5). In a 27-month-old boy with type 5 Bartter’s syndrome, who presented with seizure, laboratory results showed hypocalcemia, metabolic alkalosis, sever hypokalemia and a low level of PTH. Calcium and vitamin D supplements were prescribed and the seizure was controlled. There are several subtypes of Bartter’s syndrome with distinct phenotypes. Type 5 of Bartter’s syndrome results from mutation leading to upregulation of the CaSR and therefore hypocalcemia and hypercalciuria in addition to the typical salt-losing phenotype.

Keywords: Bartter’s syndrome, Calcium-sensing receptor, Metabolic alkalosis