NECTIN2 and Alzheimer disease: For Alzheimer’s disease, allelic heterogeneity was observed in the genomic locus containing NECTIN2, TOMM40, APOE and APOC1, which has been reported before [66, 67] and reflects the fact that different APOE haplotypes ε2, ε3 or ε4 can be risk factors or protective factors for Alzheimer’s disease [68–71].