Vreeswijk Maaike P G, Kraan Jaennelle N, van der Klift Heleen M, Vink Geraldine R, Cornelisse Cees J, Wijnen Juul T, Bakker Egbert, van Asperen Christi J, Devilee Peter
Center for Human and Clinical Genetics, Leiden University Medical Center (LUMC), Leiden, The Netherlands.
Hum Mutat. 2009 Jan;30(1):107-14. doi: 10.1002/humu.20811.
A large number of sequence variants identified in BRCA1 and BRCA2 cannot be distinguished as either disease-causing mutations or neutral variants. These so-called unclassified variants (UVs) include variants that are located in the intronic sequences of BRCA1 and BRCA2. The purpose of this study was to assess the use of splice-site prediction programs (SSPPs) to select intronic variants in BRCA1 and BRCA2 that are likely to affect RNA splicing. We performed in vitro molecular characterization of RNA of six intronic variants in BRCA1 and BRCA2. In four cases (BRCA1, c.81-6T>A and c.4986+5G>T; BRCA2, c.7617+2T>G and c.8754+5G>A) a deleterious effect on RNA splicing was seen, whereas the c.135-15_-12del variant in BRCA1 showed no effect on RNA splicing. In the case of the BRCA2 c.68-7T>A variant, RNA analysis was not sufficient to establish the clinical significance. Six SSPPs were used to predict whether an effect on RNA splicing was expected for these six variants as well as for 23 intronic variants in BRCA1 for which the effect on RNA splicing has been published. Out of a total of 174 predictions, 161 (93%) were informative (i.e., the wild-type splice-site was recognized). No false-negative predictions were observed; an effect on RNA splicing was always predicted by these programs. In four cases (2.5%) a false-positive prediction was observed. For DNA diagnostic laboratories, these programs are therefore very useful to select intronic variants that are likely to affect RNA splicing for further analysis.
在BRCA1和BRCA2中鉴定出的大量序列变异无法区分为致病突变或中性变异。这些所谓的未分类变异(UVs)包括位于BRCA1和BRCA2内含子序列中的变异。本研究的目的是评估使用剪接位点预测程序(SSPPs)来选择BRCA1和BRCA2中可能影响RNA剪接的内含子变异。我们对BRCA1和BRCA2中六个内含子变异的RNA进行了体外分子特征分析。在四个案例中(BRCA1,c.81 - 6T>A和c.4986 + 5G>T;BRCA2,c.7617 + 2T>G和c.8754 + 5G>A)观察到对RNA剪接有有害影响,而BRCA1中的c.135 - 15_-12del变异对RNA剪接没有影响。对于BRCA2的c.68 - 7T>A变异,RNA分析不足以确定其临床意义。使用六个SSPPs来预测这六个变异以及BRCA1中已发表对RNA剪接有影响的23个内含子变异是否预期会对RNA剪接产生影响。在总共174个预测中,161个(93%)是有信息价值的(即野生型剪接位点被识别)。未观察到假阴性预测;这些程序总是预测会对RNA剪接产生影响。在四个案例中(2.5%)观察到假阳性预测。因此,对于DNA诊断实验室来说,这些程序对于选择可能影响RNA剪接的内含子变异进行进一步分析非常有用。