慢性进行性眼外肌麻痹与线粒体DNA缺失的关系

PARTIAL DELETION OF MITOCHONDRIAL DNA IN CHRONIC PROGRESSIVE EXTERNAL OPHTHALMOPLEGIA

目的： 对 ２ 例慢性进行性眼外肌麻痹（ｃｈｒｏｎｉｃ ｐｒｏｇｒｅｓｓｉｖｅ ｅｘｔｅｒｎａｌｏｐｈｔａｌｍ ｏｋｅｇｉａ，ＣＰＥＯ）患者的骨骼肌中的线粒体ＤＮＡ（ｍ ｔＤＮＡ）进行缺失突变分析。方法：用Ｓｏｕｔｈｅｒｎ 杂交和放射自显影等方法。结果：在２ 例ＣＰＥＯ 患者的骨骼肌标本中均存在线粒体ＤＮＡ 的单一的大片段缺失突变；缺失的长度分别为４．５ｋｂ 和５．５ｋｂ；突变型ｍ ｔＤＮＡ 在总体ｍ ｔＤＮＡ 中所占的比例分别为６４．６％ 和６４．２％ 。结论：上述发现支持ｍ ｔＤＮＡ 的缺失突变为ＣＰＥＯ

Objective:To characterize the deletions of mitochondrial DNA in two Chinese patients with chronic progressive external ophthalmoplegia(CPEO)and identify deletions of mtDNA as the etiology of this disease.Methods:Total DNA was isolated from frozen muscle and was digested with Pvu Ⅱ.The zymolytic products was separated by agarose gel electrophoresis,then transferred to nitrocellulose membrane and hybridized with 32 P labeled mtDNA.Results:A large scale deletions of mtDNA were identified in two patients with CPEO.The lenth of deletion of mtDNA was 4.5kb in case 1 and 5.5kb in case 2. Mutated mtDNA accounted for 64.6% and 64.2% of total mt DNA in case 1 and case 2 respectively.Conclusion:the deletions of mtDNA are important causes of physical defect in CPEO.