The APOE gene encodes apolipoprotein E, which has a central role in lipid metabolism, both in plasma and in the brain, and is a strong genetic risk factor for Alzheimer disease.43 Our GWAS and previous studies based on a candidate gene approach5,6 indicate that the APOE locus also contributes to the genetic susceptibility to ICH. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.