Cystic fibrosis and the phenotypic expression of autosomal dominant polycystic kidney disease

Recent experiments in cultured cyst epithelial cells from kidneys of patien ts with autosomal dominant polycystic kidney disease (ADPKD) have shown tha t the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) is pr esent in the apical surface of these cells and mediates chloride (Cl-) and fluid secretion in vitro, To determine whether the presence of CF with the expression of mutated CFTR proteins modifies cyst formation in ADPKD, we st udied a large family with both inherited diseases. ADPKD in this family is linked to PKD1, The family is composed of 26 members; 11 members with ADPKD , 4 members with CF, and 2 members with both diseases, Renal volumes measur ed by computerized tomography (CT), calculated creatinine clearances, and o ther clinical parameters in the family members with ADPKD and CF were compa red with those in the family members with ADPKD alone, as well as to a larg e population of patients with ADPKD. The patients with CF and ADPKD, but no t the OF heterozygote carriers with ADPKD, had less severe polycystic kidne y and liver disease, as indicated by normal renal function; smaller renal v olume, even when corrected for height and body surface area; and the absenc e of hypertension and liver cysts. These observations suggest that the coex istence of CF may reduce the severity of ADPKD, (C) 1998 by the National Ki dney Foundation, Inc.