A novel heterozygous mutation in the ATP6V0A4 gene encoding the V-ATPase a4 subunit in an adult patient with incomplete distal renal tubular acidosis.
A 40-year-old Japanese man who had a medical history of hypokalemic periodic paralysis 4 months prior was hospitalized to undergo a cholecystectomy. Hypokalemia, nephrocalcinosis and alkaluria suggesting distal renal tubular acidosis (dRTA) were detected, but metabolic acidosis was not evident. An ammonium chloride/furosemide-fludrocortisone/bicarbonate loading test demonstrated a remarkable disability in urinary H(+) excretion. A novel heterozygous mutation in the ATP6V0A4 gene encoding the vacuolar H(+)-ATPase (V-ATPase) a4 subunit p.S544L was detected. Among cases of V-ATPase a4 mutations, this is the first case in which a heterozygous mutation developed to an incomplete or latent form of dRTA.
Department of Nephrology , Itabashi Chuo Medical Center , Tokyo , Japan.
Eri
E
Imai
Department of Nephrology , Itabashi Chuo Medical Center , Tokyo , Japan.
Shuzo
S
Kaneko
Department of Nephrology, Graduate School of Medical and Dental Sciences , Tokyo Medical and Dental University , Tokyo , Japan.
Takayasu
T
Mori
Department of Nephrology, Graduate School of Medical and Dental Sciences , Tokyo Medical and Dental University , Tokyo , Japan.
Tomokazu
T
Okado
Department of Nephrology, Graduate School of Medical and Dental Sciences , Tokyo Medical and Dental University , Tokyo , Japan.
Shinichi
S
Uchida
Department of Nephrology , Itabashi Chuo Medical Center , Tokyo , Japan.
Yusuke
Y
Tsukamoto
ATP6V0A4; V-ATPase a4 subunit; distal renal tubular acidosis (dRTA); heterozygous mutation