A survey of 29 families with Adult Polycystic Kidney Disease (ADPKD) was performed to evaluate the genetic heterogeneity of the disease in Italy. The approach was through the linkage between the disease and 2 polymorphic DNA fragments as detected by the probes 3'HVR and 24.1. Linkage between the polymorphic markers and the disease was confirmed, with the following lod scores: between 3'HVR and ADPKD1 = 12.974 at theta = 0.02; between 24.1 and ADPKD = 1.716 at theta = 0.07; between 3'HVR and 24.1 = 2.738 at theta = 0.09. No evidence of significant genetic heterogeneity in the examined Italian regions was detected.