In addition, 21 participants were identified to be heterozygous or homozygous for the APOE (MIM: 107741) e4 allele, which is associated with increased lifetime risk for developing Alzheimer's disease (MIM: 104310) (Corder et al. 1993; Bertram et al. 2010). This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.