OBJECTIVETo study the characteristics of RB1 gene mutations in Chinese patients with retinoblastoma.

METHODSPeripheral blood samples of 35 patients with retinoblastoma were collected and genomic DNA was extracted. Multiplex PCR sequencing was carried out to identify RB1 gene mutations. Parents of 6 probands with RB1 mutations were also enrolled to identify the origins of mutations.

RESULTSFourteen patients were found to have carried germline mutations, among whom 11 had bilateral tumors and 3 had unilateral tumors. Sixteen germline mutations were identified, among which 13 were pathological, which included 5 nonsense mutations (c.1072C > T, c.1333C > T, c.1363C > T, c.1399C > T, c.2501C > A), 4 missense mutations (c.920C > T, c.1346G > A, c.1468G > A, c.1861C > A), 2 frameshift mutations (c.1947delG, c.2403delA) and 2 large fragment deletions (c.139_168 del30, exon 8 deletion). Three were non-pathological mutations, including 2 intronic mutations (c.540-23 dupT, c.2664-10T > A) and 1 silent mutation (c.2192T > A). One carrier was identified among the 6 parents of children carrying a RB1 mutation.

CONCLUSIONScreening for RB1 gene mutations in patients with bilateral or unilateral retinoblastoma can help to identify heritable mutations and provide important clues for genetic counseling and clinical management.