Open AccessA rare case of autosomal recessive ATP6V0A4 variant of distal renal tubular acidosis in a young female with recurrent nephrolithiasis
Author(s) -
Priya Haridas Anupama,
Georgi Abraham,
Lakshmi Shanmugasundaram,
Sneha Haridas Anupama
Publication year - 2019
Publication title -
saudi journal of kidney diseases and transplantation/našrat amraḍ wa zira'aẗ al-kulaẗ
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.268
H-Index - 30
eISSN - 2320-3838
pISSN - 1319-2442
DOI - 10.4103/1319-2442.275490
Subject(s) - nephrocalcinosis , hypercalciuria , distal renal tubular acidosis , medicine , nonsense mutation , hypokalemia , endocrinology , metabolic acidosis , frameshift mutation , mutation , renal tubular acidosis , distal convoluted tubule , reabsorption , microbiology and biotechnology , kidney , acidosis , missense mutation , excretion , gene , genetics , biology
Homozygous autosomal recessive distal renal tubular acidosis (dRTA) is a rare entity. The intercalated cells in the collecting ducts are defective in apical proton secretion or basolateral bicarbonate reabsorption, due to mutations in genes encoding for proteins in a4 and B1 subunits of the V-ATPase and the anion exchanger Cl - /HCO - (kAE1). This results in decreased ammonium (NH 4 + ) excretion and defective urine acidification. dRTA is characterized by hyperchloremic metabolic acidosis with normal anion gap, hypokalemia, hypercalciuria, hypocitranuria, and nephrocalcinosis. Autosomal recessive dRTA is associated with mutation in ATP6V1B1 (2p13) or ATP6V0A4 (7q34) genes. ATP6V1B1 mutation is associated with early - onset sensory neural hearing loss (SNHL), whereas ATP6V0A4 gene mutation may be associated with early-to late-onset SNHL. We report the case of a 30-year-old married woman diagnosed with dRTA at three months of age with mild SNHL, showing homogygous nonsense mutation in exon 3 of the ATP6V0A4 gene that resulted in a stop codon and premature truncation of the protein at codon 6.