巴金森氏病之基因易感性

Genetic Susceptibility in Parkinson's Disease

巴金森氏病為一種臨床上常見的神經退化性疾病，導因於黑質紋狀系統的原發性退化。臨床上分為兩型，即家族型及偶發型。有關家族型巴金森氏病，近年來的研究，已檢驗出部分的家族型巴金森氏病存在有特定的基因缺陷，而同卵雙胞胎的研究發現有較高罹患巴金森氏病的一致性、並且在巴金森氏病患者的家族成員中，發現罹患巴金森氏病的危險性增加。這些累積的證據顯示遺傳基因在巴金森氏病的致病機轉扮演著重要的角色。至於偶發型巴金森氏病的病患，最近有關易感性基因用以解釋此疾病遺傳部份的假說已逐漸被重視。但是至今為止，尚未有任何一種基因被證實與偶發型巴金森氏病有關。由於環境因素與此疾病盛行率增加有關，而且某些特定毒素已被證實會引發黑質細胞的退化，因此單用遺傳的觀點來解釋偶發型巴金森氏病並不適合。除外，大腦內源性毒素的生成也可能在巴金森氏病的致病過程中啟動黑質細胞的死亡。無論如何，巴金森氏病的致病機轉可能起因於遺傳基因、環境因子、有毒物質間的交互作用及相互影響而導致。

Parkinson's disease is a common neurodegenerative disease, resulting from primary degeneration of the nigrostriatal system. Recently, accumulating evidences showed that genetic factors might play an important role in its pathogenesis. The occurrence of familial disease with identified gene defects, an increased prevalence in homozygous twin pairs, and the existence of family clusters were been reported. Since sporadic cases of Parkinson's disease has been noted, an involvement of susceptibility genes has been proposed to explain the inherited component of the disorder. However, to date most studies have failed to identify a specific genotype related to the occurrence of Parkinson's disease. In contrary, a genetic component may not be necessary to explain the sporadic occurrence of Parkinson's disease, since environmental factors ate also associated with an increased prevalence of the illness, and use actions of specific toxins are also known to induce nigral cell degeneration. Furthermore, endogenous toxin formation in the brain leads to a variety of processes that initiate nigral cell death in Parkinson's disease. In conclusion, the association of either genetic, environmental, or toxic components may contribute to the occurrence of Parkinson's disease, and interaction between these factors can result to nigral cell degenerations.