[Nephrolitiasis in a patient with cystic fibrosis]

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Defects in the CFTR gene cause abnormal chloride conductance across the apical membrane of epithelial cells, which results in progressive lung disease and also affects other organs. Because life expectancy has increased, other complications of CF have become more apparent. We present a patient with CF and symptomatic nephrolithiasis. Several stones were evident in both kidneys. A 24-hour urine sample showed hyperoxaluria (141 mg/24 h/ 1.73 m(2)) and hypocitraturia and (206 mg/24 h/1.73 m(2), 177 mg citrate/g creatinine). Nephrolithiasis should be included in the differential diagnosis of patients with CF and abdominal pain; urinary excretion of oxalate and citrate should be investigated.