In this study we evaluated the association of the recently discovered [1] variants in the microglia-enriched genes ABI3 and PLCG2 in AD and four other neurodegenerative diseases comprised of three α-synucleinopathies (PD, DLB, MSA) and a primary tauopathy (PSP); investigated an African-American AD case-control cohort for presence and frequency of these variants; and studied the expression patterns of these genes in two brain regions (temporal cortex, cerebellum) in AD vs. control; and PSP vs. control samples. This evidence concerns the gene PLCG2 and Alzheimer disease.