Dravet综合征患者SCN1A基因启动子区突变位点的检测及分析

Screening and analysis of SCN1A promoter mutations from Dravet sydrome

目的对Dravet综合征患者SCN1A基因启动子区突变位点进行筛查及分析,预测其致病易感性。方法收集24例Dravet综合征患者及100例正常人的外周血,抽提基因组DNA,PCR扩增SCN1A基因启动子区序列并测序;用生物信息学方法分析了SCN1A启动子区变异位点邻近序列的保守性及潜在的结合元件,推测其致病易感性。结果从患者中发现两个突变位点-244 C>T和-662 G>-,都来自父亲,而没有血亲关系的正常人中没有发现;-244和-662突变位点在哺乳动物中高度保守(100%);人与其他哺乳动物之间-244突变位点邻近序列(位点上、下游20个碱基)的平均同源率高达90%,而-662突变位点邻近序列的平均同源率只有60%;含-244位点的序列分别能预测到4种不同的转录因子结合元件,而含-662位点的序列均未能预测到。结论这两个突变与疾病存在一定程度的相关性,其致病的机制有待于实验证实。

Objective To screen and analyze the mutation of SCN1A promoter regions from patients with Dravet syndrome and to evaluate the relationship between mutation and the disease. Methods Peripheral blood of 24 patients with Dravet syndrome and 100 controls were collected and genomic DNA was extracted. PCR and sequencing of SCNIA promoter region were then performed. To evaluate the possibility of mutation inducing disease, analyzed the conservation of the sequences including the mutation sites and predict the potential transcriptional elements. Results Two mutations - 244 C 〉 T and - 662 G 〉 - were identified from patients and both mutations were found in their farther genomic DNA, but not in unrelated normal persons. The nucleotide sites -244 and -662 were highly conserved in mammals （100%）. The average nucleotide identity rate of -244 adjacent sequences （20 bp upstream and downstream of the mutation sites） between human and other species reached 90%, and was only 60% for that of -662. Potential transcription regulatory elements and factors were found on the sequence including -244, but not on the sequence including -662. Conclusion The two mutations may be associated with Dravet syndrome and further studied should be performed to demonstrate their pathogenic mechanisms.