SLC4A5 and hypertensive disorder: Although further experimental evidence is required to test this hypothesis, it has for instance been suggested that knockout of NBCe2—which is expressed in the renal collecting ducts (Damkier et al., 2007; Gröger et al., 2012)—causes hypertension because of a compensatory increase in NBCn1 transport activity (Gröger et al., 2012).