Skipping of FCER1G Exon 2 Is Common in Human Brain But Not Associated with the Alzheimer's Disease Genetic Risk Factor rs2070902.

Background: Understanding the mechanisms whereby genetic variants influence the risk of Alzheimer's disease (AD) may provide insights into treatments that could reduce AD risk. Objective: Here, we sought to test the hypothesis that a single nucleotide polymorphism (SNP) associated with AD risk, rs2070902, influences splicing of FCER1G exon 2. Methods: AD and non-AD brain samples were analyzed for FCER1G expression by genotyping, immunohistochemistry, immunofluorescence, and qPCR. Results: The protein encoded by FCER1G, FcRγ, is robustly expressed in microglia in both AD and non-AD brain. The FCER1G isoform lacking exon 2 (D2-FCER1G) was readily detectable. Moreover, the proportion of FCER1G expressed as this isoform was increased in brains with high AD neuropathology. However, the proportion of FCER1G expressed as the D2-FCER1G isoform was not associated with rs2070902 genotype. Conclusions: In summary, the proportion of FCER1G expressed as the D2-FCER1G isoform is increased with AD neuropathology but is not associated with rs2070902.