Our own previous study [9], with 55 cases of AD and 73 controls from the Oxford Project to Investigate Memory and Ageing (OPTIMA), suggested an association with AD of two alleles in linkage disequilibrium with each other, HLA-B7 and HLA-Cw*0702, especially in people without the ε4 allele of apolipoprotein E (APOE4). The gene discussed is APOE; the disease is Alzheimer disease.