Background: In the present study we determined whether the cystatin c gene (CST3) is genetically associated with late-onset Alzheimer's disease (AD).
Methods: Two informative flanking single nucleotide polymorphisms (SNP), rs2424577 and rs3827143, of the CST3 gene and apolipoprotein E (APOE) gene were assessed in 568 Finnish AD patients and 688 cognitively healthy controls. Samples were genotyped with the TaqMan technique, and we conducted a single allele and genotypic distribution comparison as well as an estimation of haplotype frequencies between cases and controls.
Results: The APOE genotype distribution differed as expected between the AD cases and controls (p < 0.001). On the whole, any significant differences in AD risk were not found in single SNP and haplotype analyses for the CST3 gene between the whole study cohorts or in the stratified subgroups. Interestingly, AG-genotype carriers of rs3827143 showed a significant difference (p = 0.04) between cases and controls when compared to AA-genotype carriers, but this finding remained insignificant in the adjusted model.
Conclusion: Although flanking SNP cover the whole gene transcript with strong linkage disequilibrium, our data show that the CST3 gene is not associated with AD risk in the Finnish population.