Use of single strand conformation polymorphism analysis to detect point mutations in human mitochondrial DNA.
Myoclonus epilepsy with ragged-red fibers (MERRF) has been shown to be associated with a specific point mutation at the nucleotide 8344 in the tRNA(Lys) gene of mitochondrial DNA (mtDNA). We screened 6 patients with clinically diagnosed MERRF and 1 patient with ocular myopathy for point mutations in the tRNA(Lys) gene, using single strand conformation polymorphism (SSCP) analysis, which can detect even a 1-basepair difference between 2 DNA sequences. Using SSCP and consequent DNA sequencing, we identified the known MERRF mutation in 4 out of 6 MERRF patients, as well as in 1 patient with a new clinical phenotype associated with this mutation: progressive external ophthalmoplegia, muscle weakness and a lipoma, but no myoclonus or epilepsy. Two of the patients with clinical MERRF had neither the MERRF-mutation nor any other mutations in the tRNA(Lys) gene. Using SSCP analysis, we also detected a new polymorphism in 1 patient. Thus, SSCP analysis can be applied to search effectively and rapidly for point mutations or polymorphisms in mitochondrial DNA.
Suomalainen
A
A
Department of Neurology, Columbia University, New York, NY.
Ciafaloni
E
E
Koga
Y
Y
Peltonen
L
L
DiMauro
S
S
Schon
E A
EA
D000293:Adolescent; D000328:Adult; D000368:Aged; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics; D005260:Female; D006801:Humans; D017243:MERRF Syndrome / Q000235:genetics*; D008297:Male; D009690:Nucleic Acid Conformation; D009695:Nucleic Acid Renaturation; D016133:Polymerase Chain Reaction; D012357:RNA, Transfer, Lys / Q000235:genetics*
D004272:DNA, Mitochondrial; D004277:DNA, Single-Stranded; D012357:RNA, Transfer, Lys