APOC1 and Alzheimer disease: We performed first large‐scale analysis of linkage disequilibrium (LD) structures characterized by 30 polymorphisms from five genes in the APOE 19q13.3 region (BCAM,NECTIN2,TOMM40,APOE, and APOC1) in 2,673 AD‐affected and 16,246 unaffected individuals from five cohorts.