PRRT2相关发作性疾病致病基因PRRT2突变分析

发布时间：2019-06-10 18:10

【摘要】：背景：富含脯氨酸的跨膜蛋白2基因(PRRT2)编码340个氨基酸,产物为富含脯氨酸的跨膜蛋白,其功能目前尚不清楚。2011年Wang, Chen等率先在发作性运动诱发性运动障碍(PKD)中发现了该基因致病突变。随后的研究发现PRRT2基因也是良性家族性婴儿惊厥(BFIS)和婴儿惊厥伴发作性手足舞蹈徐动征(ICCA)的主要致病基因。到目前为止,国内外的研究发现了50余种PRRT2点突变,然而仍有一部分典型的PKD, BFIS, ICCA患者未检测出PRRT2点突变,提示可能为缺失突变等非常规突变或其他基因突变所致。另外,在癫痫等多种神经系统发作性疾病中也有PRRT2致病突变报道,PRRT2是否为癫痫的致病基因仍不明确,需要进一步研究证实。目的：对PKD, BFIS, ICCA家系及散发患者进行PRRT2点突变及缺失突变的筛查,建立了PKD, BFIS, ICCA基因诊断流程；对热性惊厥(FS)及特发性婴幼儿癫痫患者进行PRRT2点突变筛查,扩展PRRT2相关发作性疾病的疾病谱。方法：本研究共纳入12个PKD/ICCA家系,22个PKD/ICCA散发患者；3个BFIS/ICCA家系,28个BIS散发患者；3个FS家系,26个FS散发患者及202个特发性婴幼儿癫痫患者。利用直接测序法,对PKD,BFIS, ICCA家系及散发患者PRRT2基因的所有编码区外显子及外显子／内含子交界区序列进行点突变筛查。然后使用实时荧光定量PCR (qPCR)对未发现点突变的PKD, BFIS, ICCA患者行PRRT2缺失突变筛查。利用直接测序法,对特发性婴幼儿癫痫患者PRRT2基因的所有编码区外显子及外显子／内含子交界区序列进行点突变筛查。结果：本研究在8个PKD/ICCA家系、5个PKD/ICCA散发患者中筛查出c.649dupC (p.Arg217ProfsX8)及c.649delC (p.Arg217GlufsX12)两种已知点突变,2个PKD/ICCA散发患者中筛查出2种序列变异(c.383CT和c.412CG),3个PKD/ICCA家系、7个PKD/ICCA散发患者中筛查出PRRT2杂合缺失突变；在3个BFIS/ICCA家系、2个BIS散发患者中筛查出c.649dupC (p.Arg217ProfsX8)及c.629dupC (p.Ala211SerfsX14)两种已知点突变,2个BIS散发患者中筛查出PRRT2杂合缺失突变；在1个FS散发患者中筛查出c.649dupC (p.Arg217ProfsX8)已知点突变。结论：1.PRRT2是PKD, BFIS, ICCA的主要致病基因,该基因的杂合缺失可能是PKD, BFIS的致病原因 2.发现PRRT2新的致病点突变c.383CT(p.Ser128Phe) 3.PRRT2可能是热性惊厥的致病基因,可能不是特发性婴幼儿癫痫的常见致病基因
[Abstract]:Background: proline-rich transmembrane protein 2 gene (PRRT2) encodes 340 amino acids and the product is proline-rich transmembrane protein. Its function is not clear. 2011 Wang, Chen et al first found the pathogenic mutation in paroxysmal motor-induced motor disorder (PKD). Subsequent studies found that PRRT2 gene is also the main pathogenic gene of benign familial infant convulsion (BFIS) and infant convulsion accompanied by sexual hand and foot dance creep sign (ICCA). Up to now, more than 50 kinds of PRRT2 point mutations have been found in domestic and foreign studies. However, some typical PKD, BFIS, ICCA patients have not detected PRRT2 point mutations, suggesting that they may be caused by unconventional mutations such as deletion mutations or other gene mutations. In addition, there are also reports of PRRT2 mutation in many kinds of nervous system paroxysmal diseases, such as seizures. Whether PRRT2 is the pathogenic gene of epilepsy is still unclear, which needs to be further studied and confirmed. Objective: to screen PRRT2 point mutation and deletion mutation in PKD, BFIS, ICCA families and sporadic patients, and to establish a PKD, BFIS, ICCA gene diagnosis process. PRRT2 point mutation screening was performed in patients with febrile convulsion (FS) and infancy seizures to expand the disease spectrum of PRRT2-related paroxysmal diseases. Methods: a total of 12 PKD/ICCA families, 22 PKD/ICCA sporadic patients, 3 BFIS/ICCA families, 28 BIS sporadic patients, 3 FS families, 26 FS sporadic patients and 202 Idiopathic infant epileptic patients were included in this study. The point mutations in all coding region exons and exons / intron junction regions of PRRT2 gene in PKD,BFIS, ICCA families and sporadic patients were screened by direct sequencing. Then PRRT2 deletion mutation was screened in PKD, BFIS, ICCA patients with no point mutation by real-time fluorescence quantitative PCR (qPCR). The point mutations in all the coding region exons and exons / intron junction regions of PRRT2 gene in patients with idiopathic infant epilepsy were screened by direct sequencing. Results: two known point mutations, c.649dupC (p.Arg217ProfsX8) and c.649delC (p.Arg217GlufsX12), were screened in 8 PKD/ICCA families and 5 PKD/ICCA sporadic patients. Two sequence variants (c.383CT and c.412CG), three PKD/ICCA families and seven PKD/ICCA sporadic patients were screened for PRRT2 heterozygous deletion mutations in 2 PKD/ICCA sporadic patients. Two known point mutations of c.649dupC (p.Arg217ProfsX8) and c.629dupC (p.Ala211SerfsX14) were screened in 3 BFIS/ICCA families and 2 BIS sporadic patients, and PRRT2 heterozygous deletion mutations were detected in 2 BIS sporadic patients. The known point mutation of c.649dupC (p.Arg217ProfsX8) was screened in a patient with FS sporadic. Conclusion: 1.PRRT2 is the main pathogenic gene of PKD, BFIS, ICCA, and the heterozygous deletion of this gene may be the cause of PKD, BFIS. It was found that the new pathogenic point mutation c.383CT (p.Ser128Phe) 3.PRRT2 of PRRT2 may be the pathogenic gene of febrile convulsion, and may not be a common pathogenic gene of infancy seizures.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R742.1

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