Objective: Von Hippel-Lindau(VHL)disease is a rare autosomal dominant cancer syndrome.A phenomenon known as genetic anticipation has been documented in some hereditary cancer syndromes,where it was proved to relate to telomere shortening.Because studies of this phenomenon in VHL disease have been relatively scarce,we investigated anticipation in 18 Chinese VHL disease families.Methods: We recruited 34 parent-child patient pairs(57 patients)from 18 families with VHL disease.Onset age was defined as the age when any symptom or sign of VHL disease first appeared.Anticipation of onset age was analyzed by paired t-test and the other two special tests(HV and RY2).Relative telomere length of peripheral leukocytes was measured in 29 patients and 325 healthy controls.Onset age was younger in child than in parent in 31 of the 34 parent-child pairs.Results: Patients in the first generation had older onset age with longer age-adjusted relative telomere length,and those in the next generation had younger onset age with shorter age-adjusted relative telomere length(P<0.001)in the 10 parent-child pairs from eight families with VHL disease.In addition,relative telomere length was shorter in the 29 patients with VHL disease than in the normal controls(P=0.003).The anticipation may relate to the shortening of telomere length in patients with VHL in successive generations.Conclusions: These findings indicate that anticipation is present in families with VHL disease and may be helpful for genetic counseling for families with VHL disease families and for further understanding the pathogenesis of VHL disease.