台灣地區ARVD病人desmosome各相關基因突變之探討

Abstract

背景： 致不整脈右心室發育不全(ARVD)為一種先天遺傳性心臟缺陷，常見於40歲以下的年齡層。DSP、PKP2、DSG2和DSC2四個基因，分別表現Desmoplakin、Plakophilin-2、Desmoglein-2以及Desmocolin-2四個組成胞橋小體(Desmosome)的重要蛋白質，其基因上的缺陷影響胞橋小體的正常功能，被認為是造成致不整脈右心室發育不全的致病原因。到目前為止，在DSP、PKP2、DSG2和DSC2基因上已經有多個突變點被報導出來與致不整脈右心室發育不全有關。在本實驗中我們收集台灣地區臨床上被診斷為致不整脈右心室發育不全的病人，針對四個與胞橋小體相關的基因：DSP、PKP2、DSG2、DSC2，以基因上的Exon為研究對象，進行突變分析。 方法與結果： 我們收集了6名台灣地區的致不整脈右心室發育不全病人和50個健康人的血液，抽取血中的去氧核醣核酸(DNA)。分別就DSP的24個Exon、PKP2的14個Exon、DSG2的15個Exon以及DSC2的16個Exon，進行聚合酶連鎖反應(PCR)。將所得聚合酶連鎖反應之產物，切膠純化，以去氧核醣核酸定序的方式，對照正常的序列，去找出變異的鹼基。 在6個致不整脈右心室發育不全的病人中，我們發現了1個DSP基因上的突變點：Arg2339Gln，和3個DSG2基因上的點突變：Asn330Asp、Phe531Cys、Glu713Lys和1個mutant splice product。這5個突變點在之前的文獻中尚未被報導過，屬於新的突變點。 結論： 本篇實驗利用聚合酶連鎖反應和去氧核糖核酸定序的方式，找到5個新的與胞橋小體基因相關的突變點，將致不整脈右心室發育不全與胞橋小體之間關連性，做了初步的確認。

Background: Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited disorder of cardiac tissue that often occurs in people during the prime of life before 40 years old. There are four desmosome-related genes: DSP, PKP2, DSG2, and DSC2, which encode for four uniform desmosomal proteins: desmoplakin, plakophilin-2, desmoglein-2, and desmocollin-2. If a mutation of the above genes occurs, the normal function of desmosome may be impaired and results in the occurrence of arrhythmogenic right ventricular dysplasia. To date, a few mutations have been described. In this study, we enrolled 6 Taiwanese patients with ARVD and used polymerase chain reaction technique to screen the mutation in DSP, PKP2, DSG2, DSC2 genes. Methods and Results: We enrolled 6 Taiwanese patients with ARVD and 50 healthy volunteers. PCR protocol is set up to amplify 24exons of DSP, 14 exons of PKP2, 15 exons of DSG2, and 16 exons of DSC2. After agarose gel electrophoresis of products, we cut the correct band and purified it. The variations in nucleotides was identified using of DNA sequencing reaction. Five mutations were identified in 6 patients with ARVD, one in DSP and the others in DSG2. These mutations were Arg2339Gln (DSP), Asn330Asp (DSG2)、Phe531Cys (DSG2)、Glu713Lys (DSG2) and one mutant splice product. All of these mutations were novel mutations and have never been reported before. Conclusions: We used polymerase chain reaction and DNA sequencing reaction to screen the exons of DSP, PKP2, DSG2, DSC2, and identified 5 mutations in 6 Taiwanese patients with ARVD. These five novel mutations in desmosome-related genes further prove the relationship between ARVD and desmosome.