Autosomal Recessive Distal Renal Tubular Acidosis

An inherited form of distal renal tubular acidosis (dRTA) characterized by hypokalemic hyperchloremic metabolic acidosis. Deafness often occurs either early or later on in life but may be absent or never be diagnosed.

Epidemiology

The prevalence is unknown.

Clinical description

Disease onset usually occurs in infancy or early childhood with polyuria, polydipsia, weakness and fatigue. Failure to thrive, rickets and stunting of growth (resulting from a loss of calcium salts from the bones) are common manifestations of the disease and can lead to progressive bone disease in adults. Some patients can be asymptomatic. Deafness may occur very early or later in life. Deafness is typically bilateral, progressive and unresponsive to alkali therapy.

Etiology

Autosomal recessive dRTA is due to mutations in the ATP6V1B1 (2p13) or ATP6V0A4 (7q34) genes. These genes encode kidney-specific V-ATPase 116 kDa isoform a4 and V-ATPase subunit B 1 of H+-ATPase, respectively. ATP6V1B1 mutations are usually associated with early onset deafness whereas ATP6V0A4 mutations have been reported with both early and late onset deafness but deafness can occur with either gene mutation.

Genetic counseling

This disease is inherited in an autosomal recessive manner and genetic counseling is possible.