Genetic studies indicate that most of the risk of developing late onset Alzheimer's disease, the most common form of the disease, affecting patients aged 65 years and older, is associated with genes (ie, APOE, APOJ, and SORL) that are mainly expressed by glial cells (ie, astrocytes, microglia, and oligodendrocytes).
We validated the risk for LOAD with BIN1 (rs744373), CR1 (rs6656401), and ABCA7 (rs376465), as well as the protective association for MS4A6A (rs610932) and CLU (rs11136000) variants.
We therefore explore whether the six loci in Clusterin gene (CLU) (rs9331949), Lipoprotein lipase gene (LPL) (rs1059507, rs3200218, rs3208305, rs3735964) and Low-density lipoprotein receptor related protein 6 (LRP6) (rs2160525) could modulate LOAD risk through the alteration of miRNA binding sites.
PICALM and CLU are two major risk genes of late-onset Alzheimer's disease (LOAD), and there is strong molecular evidence suggesting their interaction on amyloid-beta deposition, hence finding functional dependency between their risk genotypes may lead to better understanding of their roles in LOAD development and greater clinical utility.
Several genome-wide association studies have found that the rs11136000 polymorphism of the C allele (CLU-C) is associated with the risk for developing late-onset Alzheimer's disease (LOAD).
The Clusterin (CLU) gene, also known as apolipoprotein J (ApoJ), is currently the third most associated late-onset Alzheimer's disease (LOAD) risk gene.
Reported odds ratios and population attributable fractions (PAF) for late-onset Alzheimer's disease (LOAD) risk loci (BIN1, ABCA7, CR1, MS4A4E, CD2AP, PICALM, MS4A6A, CD33, and CLU) come from clinically ascertained samples.
A recent genome-wide association study of LOAD found the strongest evidence of association with CLU at rs1532278, in high linkage disequilibrium with rs11136000.
Clusterin gene (CLU), also known as apolipoprotein J (ApoJ), is a strong candidate gene for late-onset Alzheimer's disease (LOAD) according to the Alzgene database.
Our findings showed evidence of CR1, CLU, and PICALM and LOAD susceptibility in an independent southern Chinese population, which provides additional evidence for LOAD association apart from prior genome-wide association studies in Caucasian populations.
In order to evaluate association with these genome-wide association study-identified genes and to isolate the variants contributing to the pathogenesis of LOAD, we genotyped the top single nucleotide polymorphisms (SNPs), rs11136000 (CLU), rs3818361 (CR1), and rs3851179 (PICALM), and sequenced the entire coding regions of these genes in our cohort of 342 LOAD patients and 277 control subjects.
We also tested for epistatic interaction between these variants and APOE ε4 as well as with the previously replicated LOAD GWAS genes (CLU: rs11136000, CR1: rs3818361, and PICALM: rs3851179).
Our finding may be a reflection of linkage to the CLU susceptibility gene, in the same way as familial AD has previously been linked to the APOE locus.
Recently, two large, and independent genome wide association studies of late-onset Alzheimer's disease (AD) established association with the same rs11136000 variation in the clusterin (CLU) gene.
Recent GWAS and subsequent confirmation studies reported several single-nucleotide polymorphisms (SNPs) at the CLU, CR1 and PICALM loci in association with late-onset Alzheimer's disease (AD).
There was evidence of association for recently-reported LOAD risk loci, including BIN1 (rs7561528, p = 0.009 with, and p = 0.03 without, APOE adjustment) and CLU (rs11136000, p = 0.023 with, and p = 0.008 without, APOE adjustment), with weaker support for CR1.
A few of these novel LOAD candidate genes, namely BIN1, CLU, CR1, EXOC3L2 and PICALM, have shown consistent replication, and are thus credible LOAD susceptibility genes.