MITOCHONDRIAL-DNA MUTATIONS IN ALZHEIMERS-DISEASE

Several reports have indicated that point mutations of the mitochondri al DNA (mtDNA) contribute to the pathogenesis of Alzheimer's disease ( AD). However, other groups have failed to find similar associations be tween these mutations and AD. A recent report described a set of mutat ions in the mtDNA encoded cytochrome oxidase genes which may account f or 20% of all AD cases, We screened brain tissue from 65 AD patients f or each of these previously reported mtDNA mutations but were unable t o find an increased incidence of any of them in our AD sample. However , one patient with a mutation in the APP gene did harbour a novel mtDN A mutation (G to C at position 5705 in the tRNA(Asn) gene) that might have contributed to the very early onset of dementia in this individua l. The role of mtDNA mutations in the pathogenesis of AD remains uncle ar, but they do not appear to be primary causes but may contribute to the onset of the disease. (C) 1997 Academic Press.