The LDLR locus in Alzheimer's disease: a family-based study and meta-analysis of case-control data.

Genetic linkage studies suggest the presence of an Alzheimer's disease (AD) risk gene on chromosome 19, acting independently of apolipoprotein E (apoE), a known AD risk factor on 19q13. The low density lipoprotein receptor (LDLR) is an interesting candidate because it maps within the linked interval, and is intimately involved in cholesterol homeostasis and the function of apoE. We tested three previously reported single nucleotide polymorphisms (SNPs) within LDLR in a large sample of discordant sibships from multiplex AD families, and failed to find evidence for genetic association with disease risk. In addition, we performed meta-analyses for SNP rs5925 on published data from five independent case control samples, but did not detect any significant summary odds ratios. Based on our data, it seems unlikely that these genetic variants in LDLR make a significant contribution to AD risk in the general population.