Our results confirm the association of PICALM gene (encoding phosphatidylinositol-binding protein) in addition to APOE gene with AD susceptibility in Korean population but did not show significant associations of other susceptibility loci with AD.
The PICALM single-nucleotide polymorphism also displayed a significant effect protecting against rapid progression during pharmacogenetic assays although its observed effect displayed heterogeneity among AD therapeutic protocols (p = 0.039).
Five genomewide association studies (GWAS) in white populations have recently identified and confirmed 9 novel Alzheimer's disease (AD) susceptibility loci (CLU, CR1, PICALM, BIN1, ABCA7, MS4A gene cluster, CD2AP, CD33, and EPHA1).
We tested for association with loci previously associated with Alzheimer's disease risk and, despite the small size of the study, we detected associations with age at onset of Alzheimer's disease in Down syndrome with PICALM (β = 3.31, p = 0.011) and the APOE loci (β = 3.58, p = 0.014).
We investigated 86 single nucleotide polymorphisms (SNPs) selected from 12 genes (ABCA7, APOE, BIN1, CD2AP, CD33, CLU, CR1, EPHA1, LRAT, MS4A6A, PCDH11X, and PICALM) based on results of the recent GWAS and genotyped in 211 AD cases.
The data suggest a neural mechanism for APOE-PICALM interactions in patients with manifest AD and indicate that the PICALM genotype modulates both brain atrophy and cognitive performance in APOE ε4 carriers.
Thus, we evaluated whether PICALM showed allele expression imbalance (AEI) and whether this imbalance was associated with the AD-associated polymorphism, rs3851179.
Finally, given the potential involvement of PICALM in facilitating AD occurrence in multiple ways, it might be possible that targeting PICALM might provide promising and novel avenues for AD therapy.
Four SNPs (rs11234495, rs592297, rs676733, and rs3851179) in the PICALM gene were significantly associated with late-onset (LO)-AD in populations from Southwest China, whereas SNPs rs744373 (BIN1), rs9331942 (CLU), and rs670139 (MS4A4E) were linked to LO-AD in populations from East China.
Similarly, the more prevalent late-onset forms of AD are associated with both coding and non-coding variants in genes such as SORL1, PICALM and ABCA7 that affect the production and clearance of Aβ.
Refinements of clinical tests used as outcome measures such as clinical dementia rating-sum of boxes further reduced sample sizes; (7) the pioneering of genome-wide association studies that leverage quantitative imaging and biomarker phenotypes, including longitudinal data, to confirm recently identified loci, CR1, CLU, and PICALM and to identify novel AD risk loci; (8) worldwide impact through the establishment of ADNI-like programs in Japan, Australia, Argentina, Taiwan, China, Korea, Europe, and Italy; (9) understanding the biology and pathobiology of normal aging, MCI, and AD through integration of ADNI biomarker and clinical data to stimulate research that will resolve controversies about competing hypotheses on the etiopathogenesis of AD, thereby advancing efforts to find disease-modifying drugs for AD; and (10) the establishment of infrastructure to allow sharing of all raw and processed data without embargo to interested scientific investigators throughout the world.
To examine whether there is a genetic link for these diseases, we performed a case-control study in Chinese population to evaluate the association of AD genome-wide association studies top hits with both PD and cognitive function in PD, investigating 13 single-nucleotide polymorphisms in 9 genes (BIN1, CLU, ABCA7, CR1, PICALM, MS4A6A, CD33, MS4A4E, and CD2AP).
In summary, this updated meta-analysis highlights the involvement of PICALMrs3851179 variant in Alzheimer's disease susceptibility in Chinese population.