Mitochondrial gene defect in patients with chronic progressive external ophthalmoplegia

( views:74, downloads:0 )
Chen Qingtang()
Li Xiaodong()
Wu Lijuan()
Qi Yu()
Wu Xiru()
Journal Title:
Volume , Issue 06, 1998
Key Word:

Abstract: Objective To detect the gene defect of mitochondrial DNA(mtDNA) from skeletal muscles in 2 patients with chronic progressive external ophthalmoplegia (CPEO).Methods After extraction of mtDNA, Southern hybridization was performed after restrictive digestion by PvuⅡ, EcoRI, Hind Ⅲ, and SacI. Then, we carried out polymerase chain reaction(PCR) and the enzyme digestion of the PCR products. Finally, mtDNA sequencing was done by automatic DNA sequence analyzer. Results In case 1, a 5 kb deletion was found by Southern blot analysis and PCR. And dosage analysis showed a heteroplasmic change with 44% mtDNAs deleted. In case 2, PCR plus restriction endonuclease PvuⅡ digestion demonstrated a mutation which was confirmed by DNA sequencing to be a single base substitution (T→C) inducing a novel PvuⅡ site around 10909 on mtDNA sequence. The laser image analyzer measurement revealed the mutation was almost homologous (99.4% mutant).Conclusions In case 1, a 5 kb deletion found in mtDNA is called "common deletion" according to the literature. In case 2, a novel PvuⅡ site was found. It seems to be a de novo point mutation affecting ND4 in published CPEO research and is first reported in Chinese population. This point mutation does not induce an amino acid(Phe) change according to the published human mitochondrial genetic code as well as the mtDNA sequence. Whether it affects the translation efficiency or transportation of signals between mitochondrial and nuclear genome needs further studies.

  • [1]Zeviani M, Moreas CT, DiMauro S, et al. Deletions of mitochondrial DNA in Kearns-Sayre syndrome. Neurology 1988; 38:1339.
  • [2]DiMauro S, Moreas T. Mitochondrial encephalomyopathies. Asch Neurol 1993; 50:1197.
  • [3]Takei Y, Ikeda S, Yanagisawa N, et al. Multiple mitochondrial DNA deletions in a patient with mitochondrial myopathy and cardiomyopathy but no ophthalmoplegia. Muscle Nerve 1995; 18:1321.
  • [4]Maniatis T, Sambrook J, Fritsch EF. Molecular cloning: A laboratory mannual. 3rd ed. New York: Cold Spring Harbor Lab Press, 1987.
  • [5]Schon ER, Rizzuto R, Moreas CT. A direct repeat is a hotspot for large-scale deletion of human mitochondrial DNA. Science 1989; 244:346.
  • [6]Anderson S, Banker AT, Barrel BG. Sequence and organization of the human mitochondrial genome. Nature 1981; 290:457.
  • [7]Shanke S, Moreas CT, Lombes A, et al. Widespread tissue distribution of mitochondrial DNA deletions in Kearns-Sayre syndrome. Neurology 1990; 40:24.
  • [8]Kawashima S, Onta S, Kagawa T, et al. Widespread tissue distribution of multiple mitochondrial DNA deletions in familial mitochondrial myopathy. Muscle Nerve 1994; 17:741.
  • [9]Hattori Y, Goto Y,Sakuta R, et al. Point mutations in mitochondrial tRNA genes: sequence analysis of chronic progressive external ophthalmoplegia (CPEO). J Neurol Sci 1994; 125:50.
WanfangData CO.,Ltd All Rights Reserved
About WanfangData | Contact US
Healthcare Department, Fuxing Road NO.15, Haidian District Beijing, 100038 P.R.China
Tel:+86-010-58882616 Fax:+86-010-58882615