The neonatal variant of Bartter syndrome and deafness: Preservation of renal function

Background. A subtype of antenatal Bartter syndrome and sensorineural deafness (BSND) was originally described among families from southern Israel, and its gene (Barttin, OMIM #606412) has recently been identified. A report has suggested that these children develop chronic renal insufficiency during childhood attributable to chronic tubulointerstitial fibrosis and atrophy. Methods. Data from 13 infants with BSND, who were born during a 20-year period in our institution, were retrospectively analyzed. Results. All pregnancies were complicated by polyhydramnion and premature birth. All patients have sensorineural deafness, as well as hypokalemic metabolic alkalosis. Persistent hypercalciuria or nephrocalcinosis were absent in most children. All children have been treated with indomethacin (2 mg/kg/d) and potassium supplementation. The current average serum creatinine and calculated creatinine clearance from the older group (n = 8; mean age: 8.8 ± 1.4 years) is 60.8 ± 16.5 μmol/L and 95 ± 20 mL/min/1.73m², respectively. Kidney biopsies from two 7-year-old patients revealed mild focal tubulointerstitial fibrosis and minimal mesangial proliferation but no glomerulosclerosis. Conclusions. Early renal function deterioration is not a uniform finding among children with BSND mutations.