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目的 探讨慢性进行性眼外肌瘫痪 (chronic progressive external ophthalmoplegia,CPEO)和 Kearns- Sayre综合征 (Kearns- Sayre syndrome,KSS)的线粒体 DNA (mitochondrial DNA,mt DNA)突变特点。方法 用 Southern印迹方法检测 7例 CPEO和 4例 KSS患者的肌肉组织 mt DNA,并进一步用聚合酶链反应产物直接测序来明确缺失的具体范围 ;用聚合酶链反应 -限制性内切酶分析法检测有无 mt D-NA A32 4 3G点突变。结果 发现 5例患者 (2例 CPEO和 3例 KSS)存在 mt DNA的大片段缺失 ;1例 KSS患者存在 A32 4 3G点突变。 5例大片段缺失的大小及缺失范围各不相同 ,从 3.0～ 8.0 kb不等 ,缺失型 mt D-NA占总 mt DNA的比例为 37.6 %～ 87.0 %。聚合酶链反应产物测序表明这 5例缺失类型均未见文献报道。结论 与 CPEO和 KSS患者相关的最常见的 mt DNA突变为大片段缺失 ,A32 4 3G点突变也可在少数患者中检测到。
Objective To investigate the characteristics of mitochondrial DNA (mt DNA) mutations in chronic progressive external ophthalmoplegia (CPEO) and Kearns-Sayre syndrome (KSS). Methods The mt DNA of muscle tissue of 7 cases of CPEO and 4 cases of KSS was detected by Southern blotting method and the specific range of deletion was further confirmed by direct sequencing of polymerase chain reaction products. PCR was performed by polymerase chain reaction-restriction endonuclease assay Detection of whether mt D-NA A32 4 3G point mutation. Five patients (2 CPEO and 3 KSS) were found to have large deletions of mt DNA. One case of KSS had A32 4 3G point mutation. The size and deletion range of 5 large fragments varied from 3.0 to 8.0 kb, and the percentage of deletion mt D-NA to total mt DNA ranged from 37.6% to 87.0%. Polymerase chain reaction product sequencing showed that none of the five cases were reported in the literature. Conclusions The most common mt DNA mutations associated with CPEO and KSS patients are large fragment deletions and A32 4 3G point mutations can also be detected in a minority of patients.