M. Kaido et al., ALZHEIMER-TYPE PATHOLOGY IN A PATIENT WITH MITOCHONDRIAL MYOPATHY, ENCEPHALOPATHY, LACTIC-ACIDOSIS AND STROKE-LIKE EPISODES (MELAS), Acta Neuropathologica, 92(3), 1996, pp. 312-318
A 53-year-old Japanese woman with a point mutation in mitochondrial DN
A (tRNA(Leu(UUR)), nt3243) consistent with mitochondrial myopathy, enc
ephalopathy, lactic acidosis and stroke-like episodes (MELAS) and Alzh
eimer-type brain pathology is reported. This woman had suffered myopat
hy and psychosis without any clinical evidence of, stroke-like episode
s during the last 10 years of her life, and had died after an accident
. At autopsy 30 h post mortem, a part of the brain was snap frozen for
biochemical and histochemical studies, and the remaining part was pro
cessed for a routine examination and electron microscopy. In the brain
there were no ischemic lesions. Instead, primitive/diffuse senile pla
ques were found throughout the brain, predominantly in the frontal and
temporal lobes, while Alzheimer neurofibrillary tangles were found on
ly in the parahippocampal gyrus. These plaques were positive for beta-
protein and mostly negative for tau protein, ubiquitin, neurofilaments
, alpha-choline acetyltransferase, and acetylcholinesterase. Mutations
in codon 331 of the ND2 gene as well as codons 693, 713 and 717 of th
e beta-amyloid precursor protein gene, known to be responsible for som
e cases of familial Alzheimer disease, were not found. Furthermore, co
incidental Down syndrome was ruled out by chromosome analysis. The res
ults suggest a possible correlation between this mitochondrial DNA abn
ormality and Alzheimer-type pathology.