Content of mutant mitochondrial DNA and organ dysfunction in a patient with a MELAS subgroup of mitochondrial encephalomyopathies.
A point mutation of mitochondrial tRNALeu(UUR) gene is responsible for a MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) subgroup of mitochondrial encephalomyopathies. In most cases, the mutant mitochondrial DNA (mtDNA) coexists with normal mtDNA in a heteroplasmic manner. In order to quantify the content of mutant mtDNA, we developed a quantitative method of PCR. Using this method, the distribution of the mutant mtDNA was examined in 32 different tissues among 18 autopsied organs from a patient with MELAS, who had shown hypophyseal dysfunction. The percentage of the mutant mtDNA at nucleotide number 3243 in each tissue was ranged between 22% and 95%. The content of the mutant mtDNA was at the highest (95%) in the hypophysis and higher in the cerebral cortex than in the white matter. This study shows a possible correlation of tissue dysfunction with accumulation of the mutant mtDNA within the brain.
Shiraiwa
N
N
Department of Neurology, University of Tsukuba, Ibaraki-ken, Japan.
Ishii
A
A
Iwamoto
H
H
Mizusawa
H
H
Kagawa
Y
Y
Ohta
S
S
D000328:Adult; D001345:Autoradiography; D001923:Brain Chemistry / Q000502:physiology; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006801:Humans; D017241:MELAS Syndrome / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D010901:Pituitary Function Tests; D010904:Pituitary Gland, Posterior / Q000502:physiology; D010909:Pituitary Hormones, Posterior / Q000097:blood; D017354:Point Mutation; D016133:Polymerase Chain Reaction
D004272:DNA, Mitochondrial; D010909:Pituitary Hormones, Posterior