Hypokalemia and hearing loss in a 3-year-old boy: Questions.

Bartter syndrome with sensorineural deafness (Bartter syndrome type 4) is an autosomal recessive disorder characterized with polyhydramniosis, premature birth, massive polyuria, renal salt-wasting, hypokalemic metabolic alkalosis, normotensive hyperreninemic hyperaldosteronism, and hearing loss. Homozygous mutations in BSND, CLCNKA, and CLCNKB mutations cause the disorder. Here we report a 3-year-old boy who had not been evaluated and investigated before cochlear implantation. Hypokalemia was detected during the routine laboratory workup before surgery. Further analyses revealed metabolic alkalosis with high renin and aldosterone levels. Hypokalemia improved with oral potassium chloride supplementation. Genetic tests revealed a homozygous c.139G>A (pG47R) mutation in BSND gene, and both parents were heterozygous for the same mutation. We want to emphasize the importance of evaluating hearing loss in children, since some of the genetic syndromes may cause life threatening abnormalities.