[Molecular diagnosis of retinoblastoma. First experience in Russia]

The first experience with molecular diagnosis of retinoblastoma (RB) in Russia is presented. A protocol based on the use of up-to-date molecular diagnostic methods helps detect structural and functional abnormalities in RB1 gene, diagnose RB in disputable cases and at early stages of the disease. Forty-five families with various forms of RB were examined. Twenty-three mutations in various sites of RB1 gene were characterized. Abnormal methylation in the promotor area of RB1 gene was detected in 20% cases and loss of heterozysity by intragene microsatellite markers was detected in 70% cases. Hence, the causes of RB were detected in 80% families, which led to early diagnosis in close relatives of patients and helped evaluate the repeated risk of the tumor in families of patients with RB.