Is the LDL receptor-related protein involved in Alzheimer's disease?

LDL-related protein receptor (LRP) is the main receptor in the brain for apolipoprotein E. Moreover, the LRP gene is located on chromosome 12, the site of a potential Alzheimer's disease (AD) locus. We explored the association between the LRP gene and AD in 600 French Caucasian patients (37.8% men, mean age 72.0+/-8.0 years, mean age at onset 68.7+/-8.1 years) and age-matched controls (n=646, 37.0% men, mean age 72.5+/-8.2 years) and observed an association between a (TTTC) repeat at the 3' end of an Alu sequence in the LRP gene and the risk of developing AD. Three alleles were detected in this population [corresponding to 83, 87, and 91 base pairs (bp)], the 91-bp allele being associated with an increased risk of developing AD [all patients: odds ratio (OR) 1.6, P<0.01; late-onset AD: OR 1.8, P<0.01]. This suggests an association between the LRP locus and AD. However, in the light of studies related to the exon 3 LRP polymorphism and given the low strength of the association reported here, a biologically active variant may exist on chromosome 12, either in the LRP gene itself or in another gene in the vicinity.