Mitochondrial DNA variants in a Japanese population of patients with Alzheimer's disease.

The evidence for the role of mitochondria in Alzheimer's disease (AD) has been well investigated, based on the amyloid hypothesis and its relation to the mitochondrial dysfunction due to oxidative stress. However, contrasting reports describe an unclear picture on the relationship between AD and mitochondrial DNA (mtDNA) variations. Therefore, we analyzed complete mtDNA sequences from 153 AD patients and 129 normal control subjects to determine if inherited mtDNA polymorphisms or rare variants, or both contribute to the etiology of late-onset AD.

A novel mtDNA C11777A mutation in Leigh syndrome.

A novel mitochondrial DNA point mutation, a C-to-A mutation at nucleotide position (np) 11,777, was identified in two unrelated patients out of 100 with Leigh syndrome. This mutation converted a highly evolutionary conserved arginine to a serine at codon 340 in ND4 gene. This codon was also converted by a G-to-A mutation at np 11,778, the most common mutation associated with Leber's hereditary optic neuropathy (LHON), but the amino acid replacement was different (R340S vs.

A double mutation (G11778A and G12192A) in mitochondrial DNA associated with Leber's hereditary optic neuropathy and cardiomyopathy.

We report a male patient with Leber's hereditary optic neuropathy (LHON) and hypertrophic cardiomyopathy. Besides a G11778A mutation in the ND4 gene of the mitochondrial DNA (mtDNA), one of the most common mutations in LHON patients, sequencing of total mtDNA revealed a G12192A mutation in the tRNA (His) gene that was recently noted to be a risk factor for cardiomyopathy. Because no case of LHON presenting with cardiomyopathy has been reported, the present finding suggests that the G12192A mutation caused cardiomyopathy as an additional symptom.