OBJECTIVETo explore the genetic difference between mild cognitive impairment (MCI) and Alzheimer's disease (AD) through association analysis of whole genome sequencing data.

METHODSSequence data of 168 AD patients, 380 MCI patients and 261 elderly controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI) project was collected. The genotype and phenotype association was analyzed through genome wide association study (GWAS).

RESULTSSixteen single nucleotide polymorphisms (SNPs) were found to be associated with AD, and most of them were located on chromosome 19. This was consistent with the results of previous studies. Ten SNP loci were associated with MCI, and most of them were located on chromosome 9. The biological pathways associated with the SNP sets were calculated with a Plink Sets-based algorithm, and the results showed that the SNP loci sets associated with MCI and AD belonged to different biological pathways.

CONCLUSIONThe strictly adjusted result indicated that the SNP loci significantly associated with MCI and AD are different, and the nominal significant associated SNP loci showed that steady MCI and AD shared just a limited number of loci. This indicated that MCI and AD are different diseases bearing distinct genetic risks.