Molecular Genetics Of Chronic Progressive Extraocular Muscle Paralysis

Objective To study mitochondrial DNA(mtDNA) mutations in chronic progressive external ophthalmoplegia(CPEO), and explore the genetic pathogenesis of the disease. Methods The mtDNA deletion mutation, tRNA(Leu) gene A3243G point mutation and other point mutations in tRNA(Leu) gene in the peripheral blood mononuclear cells (PBMC) and the affected extra-ocular muscles (7 muscles including levator muscle of upper eyelid) of 4 CPEO patients and 10 ocular diseases (except CPEO) patients were detected by polymerase chain reaction(PCR), PCR combined with restricted fragment length polymorphism(PCR-RFLP) and PCR combined single strand conformation polymorphism(PCR-SSCP) respectively. Results ?The mtDNA deletion mutation was found in one CPEO patient抯 affected extra-ocular muscle (levator muscle of upper eyelid), but not in his PBMC; @~The tRNA(Leu) gene A3243G point mutation was not found in all the patients with or without CPEO; ?Other point mutations in tRNA(Leu) gene were not found. Conclusions ?The deletion mutation of mitochondrial DNA is related to the pathogenesis of -3- CPEO; ~ The deletion mutation can occur in affected extra-ocular muscles, but not in PBMC in the same patient ; ?The specific mutation ?tRNA(Leu) gene A3243G of mitochondrial encephalomyopathies with lactic and stroke-like episodes(MELAS ) is not found; ?Other point mutations in tRNA(Leu) gene are not found.