RHCG and renal tubular acidosis: In multiple conditions of altered ammonia excretion, including metabolic acidosis, reduced renal mass, hypokalemia, cyclosporine‐induced renal tubular acidosis, and ischemia reperfusion injury, there are parallel changes in Rhcg expression (Seshadri et al. 2006a,b; Han et al. 2007, 2011; Kim et al. 2007; Lim et al. 2008).