The major haplotype, H1, has been genetically associated with increased risk for multiple neurodegenerative disorders, including APOE ɛ4-negative Alzheimer’s disease (AD) [1], corticobasal degeneration (CBD) [2], progressive supranuclear palsy (PSP) [3–5] and Parkinson’s disease (PD) [6–10]. The gene discussed is APOE; the disease is Alzheimer disease.