臺灣地區強直型肌肉萎縮症盛行率之調查及遺傳特性之研究

強直型肌肉萎縮症(Myotonic Dystrophy；DM)是一體染色體顯性遺傳(autosomal dominant)疾病。在臨床症狀的表現上主要包括肌肉收縮後不易放鬆、肌肉(臉部、頸部、和四肢)無力及漸進性萎縮等。除此之外，亦可能影響眼睛、腦、皮膚、肺等器官及內分泌系統而出現白內障、智能障礙、禿頭、肺炎、糖尿病、和男性不孕等症狀。造成此一多系統疾病的主要原因係因位於第十九對染色體長臂(19q13.3)上一段CTG三聯核酸重複序列發生擴增突變所導致。 雖然DM被認為是遺傳性神經肌肉疾病中最普遍的一種，然而其分佈亦有區域性差別。目前，台灣地區沒有確切的發生率報告，由於正常人口中CTG重複序列數目之分佈狀況可概估DM盛行率，我們依實驗結果推估台灣地區之DM盛行率可能低於歐美及日本。同時，我們收集及鑑定出十一個DM家族，共二十三位DM患者及尚未發病者，發現有anticipation現象，且台灣地區DM的遺傳特性大致上與歐美及日本等地區類似。此外，基於DM與Alu+/-多型性連鎖不平衡之關係，我們調查了正常範圍內CTG重複序列數目與Alu+/-多型性之關聯性，其結果顯示不同族群中CTG序列數目與Alu+/-多型性之聯鎖不平衡關係可能並不一樣。

Myotonic dystrophy ( DM ) is an inherited, autosomal dominant disorder characterized primarily by myotonia (face, neck, and limbs), progressive muscular dystrophy, mental retardation, cardiac conduction defects, and testicular tabular atrophy. The molecular event underlying DM has been identified as an expansion mutation of a (CTG)n trinucleotide repeat sequence in the region of chromosome 19q13.3. Although DM is considered to be the most prevalent inherited neuromuscular disease of adults, the prevalence is different from one population to another in the worldwide. Based on our investigation, the DM prevalence in Taiwan could be much lower than that in Caucasian and Japanese population. To data, we have identified 23 DM patients and carriers who belong to 11 families by determining the CTG repeat length. The genetic characteristics of DM in Taiwanese population are very similar to those described previously, including” phenomenon of anticipation”. In addition, by the study of the linkage disequilibrium between Alu+/- polymorphism and CTG repeat lengths, we found that it could vary to some extent in different populations.