The gene encoding phospholipase C gamma 2 (PLCγ2) was recently linked by whole‐exome microarray genome‐wide association (rs72824905/P522R, P = 5.38 × 10−10) to Alzheimer’s disease (AD), the most common form of dementia (Qiu et al, 2009). This evidence concerns the gene PLCG2 and early-onset autosomal dominant Alzheimer disease.