The CCTTT polymorphism in the NOS2A gene is associated with dementia with Lewy bodies

We report the analysis of the allele distribution of a (CCTTT)n pentanucleotide repeat within the promoter region of the NOS2A gene in DNA samples from patients with autopsy confirmed Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) type. A significant difference was observed in the allelic distribution between the control group and the DLB group (chi2 = 15.175, df = 5; p<0.01), with an increased occurrence of the eight and nine repeat alleles, and a marked under representation of the 11 repeat allele. Genotype frequencies in the DLB group also differed significantly from controls (p<0.012). These results suggest that variations in the NOS2A gene may predispose to the development of DLB.