HLA-A and Alzheimer disease: When using HLA genotype as a binominal variate (for example, HLA-A*02:01 vs non HLA-A*02:01) for further analysis between early and late-onset AD (categorical, early vs late), we found that HLA-A*02:01 (early-onset 31.8% vs late-onset 6.3%; p = 0.023) was identified to be associated with the age of AD onset.