Renal tubular acidosis (RTA) is a medical condition that involves an accumulation of acid in the body due to a failure of the kidneys to appropriately acidify the urine.

[1] In renal physiology, when blood is filtered by the kidney, the filtrate passes through the tubules of the nephron, allowing for exchange of salts, acid equivalents, and other solutes before it drains into the bladder as urine.

[citation needed] This failure of acid secretion may be due to a number of causes, and it leads to an inability to acidify the urine to a pH of less than 5.3.

[citation needed] This leads to the clinical features of dRTA;[1] In other words, the intercalated cells' apical H+/K+ antiporter is non-functional, resulting in proton retention and potassium excretion.

[7] In a large Asian series of Distal renal Tubular Acidosis in Sjogren's Syndrome, late diagnosis is a rule in spite of overt hypokalemic periodic paralysis in a vast majority of them[8] dRTA is the most common form of RTA diagnosed in Western countries, and can be classified as either hereditary (primary) or acquired (secondary).

Reabsorption of bicarbonate is typically 80-90% in the proximal tubule and failure of this process leads to decreased systemic buffer and metabolic acidosis.

Mutations in the gene encoding this enzyme give rise to an autosomal recessive syndrome of osteopetrosis, renal tubular acidosis, cerebral calcification, and mental retardation.

[16][17][18] It is very rare and cases from all over the world have been reported, of which about 70% are from the Maghreb region of North Africa, possibly due to the high prevalence of consanguinity there.

[24] Researchers published in PLOS ONE in 2009 speculated that the infamously afflicted Charles II of Spain may have suffered from renal tubular acidosis in tandem with combined pituitary hormone deficiency.