2013-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/646154摘要：本研究之背景及重要性Brugada症候群是一種具遺傳性的心因性猝死症候群，而在東南亞是好發區域，是青壯年人口猝死之重要原因之一。過去歐美的研究指出SCN5A的基因突變是Brugada症候群的致病因素，約有20-25%的Brugada症候群患者有SCN5A的基因突變，但仍有約70%的病人找不到致病基因。我們過去的研究顯示，台灣的Brugada 症候群的病人卻只有8%可在SCN5A找到致病基因，換言之，約90%台灣Brugada 症候群病人致病基因落在其他基因。最近，我們研究在這群無SCN5A突變的Brugada 症候群病人中，發現一個嶄新的可能致病基因(NALCN)，在這個計畫我們將利用另一群無SCN5A突變的Brugada 症候群病人及較大族群無Brugada 症候群的一般人去驗證這個可能的致病基因。同時我們也將利用動物實驗去探討NALCN造成Brugada 症候群的電生理致病機轉。這個Brugada 症候群可能的致病基因可做為重要的臨床Brugada 症候群的診斷參考及可作為Brugada 症候群的家屬遺傳諮詢之用。計畫之特定目標1. 我們將利用另一群無SCN5A突變的Brugada 症候群病人及較大族群無Brugada 症候群的一般人去驗證這個新發現可能為Brugada 症候群致病基因(NALCN)。2. 我們也將利用動物實驗去探討NALCN造成Brugada 症候群的電生理致病機轉，將對Brugada症候群致病機轉有更進一步的了解。研究方法過去幾年我們已從台灣各大醫學中心及醫院收集45位Brugada症候群者。我們從受試者周邊血液的白血球萃取DNA，用PCR和DNA定序方式來找出41位Brugada症候群病人沒有SCN5A突變，我們將納入300位無Brugada症候群的一般人，利用雙向DNA直接定序法去驗證這個可能的致病基因（NALCN），在另一方面，我們利用了3天大的斑馬魚去探討NALCN的電生理功能。將用30隻利用morphoilno oligo去knockdown NALCN和30隻野生型斑馬魚的分離的心臟去做電生理實驗，包括紀錄心電圖及optical mapping去探討兩組有何不同。我們預期這將對Brugada症候群致病機轉有更進一步的了解。本研究創新之處目前國外文獻顯示70%的Brugada症候群病人在SCN5A都找不到致病突變，且Brugada症候群的基因致病機轉仍不完全明白。NALCN可能是一個嶄新的Brugada症候群致病基因，目前全世界仍未報導過。這個可能的致病基因可作為重要的Brugada症候群診斷參考及基因遺傳諮詢及可做為未來在開發新的藥物治療提供新的方向。初步結果及預期成果目前Brugada症候群並無好的藥物治療，只能裝ICD在病人發生致命性心律不整時，即時電擊，這是因為對Brugada症候群的致病機轉仍不清楚。目前我們已有45位Brugada症候群病人，在台灣南北各大醫院的支持下，這是台灣目前最大的Brugada症候群族群且具亞洲人的代表性，非白人。我們之前的研究顯示國人的Brugada症候群在SCN5A突變的比例遠低於國外報告(8% 與20%)。通過這個研究，NALCN可能成為一個新的Brugada症候群致病基因，可對臨床診斷Brugada症候群提供重要的參考，亦可作為研發Brugada症候群抗心律不整藥物新的方向，為目前無有效藥物治療打開一個窗口。<br> Abstract: Introduction：Brugada syndrome (BS) is an inherited disease characterized by an increased risk of sudden cardiac death, especially in young adults (around 40 years old). Since 1998, SCN5A gene mutation has been approved of being responsible for 20-25% of this disease in Caucasian populations. The rest could not find any disease-causal gene. In our study, we found that only 8% Brugada syndrome patients in Taiwan has a SCN5A mutation(s). In another word, over 90% Brugada syndrome patients in Taiwan mutations located in other genes. Lately, we found a novel mutated gene, NALCN, that may be the disease-causal gene for Brugada syndrome patients without SCN5A mutations. In this project, we will validate this candidate mutated gene in other Brugada syndrome patients without SCN5A mutations and in a large-scale population without BS. In the meantime, we propose to use animal model to elucidate the electrophysiological function of NALCN in the development of Brugada syndrome.Objectives：1. We will validate the candidate mutated gene (NALCN) in other Brugada syndrome patients without SCN5A mutations and in a large-scale population without BS.2. We will use animal model to elucidate the electrophysiological function of NALCN in the development of Brugada syndrome. We expect to elucidate the genetic mechanism and pathogenesis of Brugada syndrome without SCN5Amutations.Methods：Forty five patients with BS were diagnosed at our hospital or referred from other medical centers or hospital in Taiwan in past years. We performed PCR and direct DNA sequencing on the SCN5A gene for these patients and found 41 BS patients without SCN5A mutations. We will enroll 300 patients without BS to validate this mutated gene using bi-directional DNA sequencing method. In the other hand, we will use embryonic zebrafish (3 day-old) to perform functional studies of NALCN gene. We will create 30 NALCN knockdown Zebrafishs and 30 wild-type Zebrafishs using Morpholino oligos. In-vitro ECG recording and optical mapping of isolated embryonic zebrafish heart will be applied. We expect to elucidate the genetic mechanism and pathogenesis of Brugada syndrome without SCN5A mutations.What is New or Innovative in this study?According the reports in Caucasian populations, 70% of Brugada syndrome patients do not have SCN5A mutations, and the genetic mechanisms and pathophysiology of BS remains unclear. NALCN is a novel mutated gene that has not been reported for Brugada syndrome in the world. It could be an important disease-causal gene for diagnosing and genetic counseling for Brugada syndrome patients and his/her family members in Taiwan and in the world.Scientific or Clinical Implication of the Expected Results：Current treatment with intra-cardiac defibrillator for Brugada syndrome is mainly supportive because no medication work effectively, and the pathophysiology of Brugada syndrome remains unclear. We have collected 45 patients with BS. With support and contribution from other hospitals, this is the largest cohort of BS in Taiwan. Our previous study disclosed much lower mutation rate of SCN5A in BS patients in Taiwan compared to that in Caucasian populations (8% vs. 20-25%). With the present study, we expect to elucidate the genetic mechanisms of NALCN as well as the pathogenesis for the disease. Anti-arrhythmic medications can therefore be designed targeting the basic pathogenesis of this disease.