Patients with Alzheimer disease (AD) typically have insidious memory failure followed by impairments in other cognitive domains. However, some patients with AD present with combinations of dyscalculia, dyspraxia, visuoperceptual, visuospatial, and spelling deficits with relatively spared memory—so-called biparietal AD.1,2 These patients often have early age at onset (younger than 65 years old) and posterior cortical atrophy on imaging. The apolipoprotein E (APOE) gene, which exists in 3 allelic forms (ε2, ε3, and ε4), is known to influence susceptibility to development of AD3; possessing an ε4 allele is also associated with earlier disease onset. We were therefore prompted to investigate APOE ε4 frequency in biparietal AD.
Schott JM, Ridha BH, Crutch SJ, Healy DG, Uphill JB, Warrington EK, Rossor MN, Fox NC. Apolipoprotein E Genotype Modifies the Phenotype of Alzheimer Disease. Arch Neurol. 2006;63(1):155-156. doi:10.1001/archneur.63.1.155