In a mouse model of Alzheimer disease for determination of the role of genotype apolipoprotein E (APOE) [which modulates CNS innate immune function in cell cultures] in disease progression, Yang et al. compared outcome after myeloablative BMT from APOE3/3 and APOE4/4 donors. The gene discussed is APOE; the disease is early-onset autosomal dominant Alzheimer disease.