儿童视网膜母细胞瘤患者RB1基因胚系突变的特征分析

Characteristics of RB1 gene mutations in Chinese patients with retinoblastoma

目的研究国内儿童视网膜母细胞瘤（retinoblastoma，RB）患者RB1胚系突变的特征及其与表型的相关性。方法收集35例RB患儿的外周静脉血标本，提取白细胞DNA，应用多重PCR测序技术检测其RB1基因的突变情况。收集其中6例R突变患儿双亲的外周静脉血标本，研究突变的遗传性。结果35例RB患者中，共发现14例（40％）患者具有RB1的胚系突变，其中双眼受累11例，单眼受累3例。共检出RBI突变16种，其中13种为致病突变，包括5种无义突变（C．1072C〉T、c．1333C〉T、C．1363C〉T、c．1399C〉T、c．2501C〉A），4种错义突变（C．920C〉T、c．1346G〉A、C．1468G〉A、C．i861C〉A），2种移码突变（C．1947del G、c．2403delA），以及2种大片段缺失突变（C．139—168del30、exon8缺失）。3种为非致病性突变，包括2种发生于内含子区的点突变（C．540—23dupT、C．2664-10T〉A）和1种同义突变（C．2192T〉A）。在6例RB1突变患儿双亲的外周血标本中，检出1例患儿母亲携带与患儿相同的突变。结论对散发的单眼或双眼RB患者进行RB1胚系突变序列分析可以鉴定其是否为遗传型病例，为RB的遗传咨询和临床管理提供依据。

Objective To study the characteristics of RB1 gene mutations in Chinese patients with retinoblastoma. Methods Peripheral 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. Results Fourteen 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, exon8 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 indentified among the 6 parents of children carrying a RB1 mutation. Conclusion Screening for RB1 gene mutations in patients with bilateral or unilateral retinoblastoma can help to identify heritable mutations and provide importance clues for genetic counseling and clinical management.