The region on chromosome 19, including the genes encoding apolipoprotein E (APOE), translocase of outer mitochondrial membrane 40 homolog (TOMM40), and apolipoprotein C1 (APOC1), is a hotspot for single nucleotide variants (SNVs) and haplotypes associated with Alzheimer’s disease and other age-related diseases, or with longevity [3,4,7,8,9,10]. The gene discussed is APOE; the disease is early-onset autosomal dominant Alzheimer disease.