Fig. 2.

Defects in the mechanism of urinary acidification: distal renal tubular acidosis (dRTA) in humans, cattle, and mice. The consequences of AE1 loss in all three species are discussed in the text. Mutations in the two H⁺-pump subunits can also cause dRTA in humans (99, 182) and mice (60, 143). Mutations in carbonic anhydrase II are associated with a generalized renal tubular acidosis in humans (181) and mice (115). In addition, disruption of Slc26a7 (212) and Kcc4 (21) in mice results in subtypes of dRTA that have yet to be observed in humans.