Hyper activation of CFTR and CaCC proteins may account for such diseases as secretory diarrhea (Morris et al., 1999) and autosomal dominant polycystic kidney disease (Li et al., 2004), while dysfunction of these proteins may lead to CF (Kerem et al., 1989; Riordan et al., 1989), chronic pancreatitis (Cohn, 2005) as well as constipation (Morris et al., 1999). The gene discussed is CFTR; the disease is autosomal dominant polycystic kidney disease.