Barttin mutations in antenatal Bartter syndrome with sensorineural deafness

Case 1 The male patient had been born at 30 weeks of gestation (weight 1,360 g) to consanguineous parents. Pregnancy was complicated by severe polyhydramnios. Findings at his physical examination were normal except for a triangular face, large eyes, protruding ears, tachypnea and retractions. He rapidly developed renal salt wasting, hyper-reninemic hyperaldosteronism, hypokalemic metabolic alkalosis, and impaired renal function [creatinine (Crea) 1.5 mg/dl]. The diagnosis of antenatal Bartter syndrome (aBS) was suspected. On day 49 oral administration of indomethacin was started (2–3 mg/kg per day), which could not help to regulate serum potassium levels. Instead, upon indomethacin treatment, renal function further deteriorated (Crea 2.5 mg/dl). Therefore, indomethacin was stopped, and he was treated with spironolactone. Potassium need declined to 27 mEq/kg, and he was discharged after 140 days. He has unilateral sensorineural deafness detected by impaired brain stem evoked potentials and growth retardation. A homozygous mutation in the Barttin gene (BSND) leading to a loss of start codon was detected (Table 1). A similar mutation has been previously described [1].