Gouty diathesis describes uric acid or calcium oxalate nephrolithiasis and low urinary pH (<5.5). A hereditary component has been outlined for several forms of nephrolithiasis (such as hypercalciuria, hyperoxaluria, cystinuria, renal tubular acidosis), leading to the hypothesis of a genetic predisposition to nephrolithiasis. At the Unit of Nephrology, Ospedali Riuniti di Bergamo, more than 100 patients affected by gouty diathesis are followed. Fifty percent of them has a familiarity for kidney stones formation. The aim of our study is to identify the genetic factors that predispose to the development of nephrolithiasis in patients with gouty diathesis.