NO ASSOCIATION FOUND BETWEEN ALZHEIMERS-DISEASE AND A MITOCHONDRIAL TRANSFER-RNA GLUTAMINE GENE VARIANT

We have screened a large sample of patients with sporadic late-onset d ementia of the Alzheimer type (DAT) and age-matched controls for a mit ochondrial tRNA(Gln) variant previously reported to be associated with increased risk of developing Alzheimer's disease (AD). The frequency of an Ava II site gain was determined by restriction analysis of a PCR -amplifled mitochondrial DNA product. One of 155 DAT cases and four of 105 age-matched controls carried the variant. Both the affected and c ontrol frequencies are statistically different from those previously r eported. The mitochondrial lineage of those individuals harboring the variant was determined by sequencing a short region of the hypervariab le mitochondrial D-loop. The affected individual and three of the four controls carrying the Ava II variant belong to the same mitochondrial lineage previously reported to be associated with AD.