In 1999, renal tubular acidosis with deafness was the first phenotype linked to the V-ATPase with mutations in the kidney-specific isoforms ATP6V1B1 (MIM 267300) or ATP6V0A4 (MIM 602722) (refs 3, 4, 5). The gene discussed is ATP6V1B1; the disease is renal tubular acidosis.