These findings represent the first evidence that in the presence of the NBCe1-A-Q29X mutation that causes proximal renal tubular acidosis, full-length functional NBCe1-A protein can be produced.
These results, together with the presence of nonfunctional mutants (Q29X and DeltaA) in other patients, suggest that at least approximately 50% reduction of NBC1 activity would be required to cause severe pRTA.