Von Hippel-Lindau (VHL) disease is an autosomal dominantly inherited condition characterized by a predisposition to the development of haemangioblastoma, renal cell carcinoma and phaeochromocytoma. The gene which, when altered, causes the disease was cloned in 1993, and maps within a series of known polymorphic loci in the 3p25-p26 region. To optimize a DNA-based presymptomatic diagnosis, we have selected six highly informative microsatellite loci, closely linked to the VHL gene. Genotyping using a multiplex-PCR approach was performed in 26 affected families including 99 asymptomatic relatives born from an affected parent. Ninety-six subjects were informative with one or more markers, 76 being informative with markers on both sides of the gene. Combination of age-related and DNA-based risk information improved the accuracy of risk assessment for 90 at-risk patients (91%) and allowed attribution of risk with a confidence limit higher than 0.98 in 79 cases (88%).