No association of psychosis in Alzheimer disease with neurodegenerative pathway genes.

Psychotic symptoms occur in approximately 40% of subjects with Alzheimer disease (AD with psychosis; AD + P) and identify a subgroup with more rapid cognitive decline. We evaluated in 867 AD subjects the association of AD + P with genes which may modify the pathological process via effects on the accumulation of amyloid beta (Aβ) protein and/or hyperphosphorylated microtubule-associated protein tau (MAPT): amyloid precursor protein (APP), beta-site amyloid precursor protein cleaving enzyme (BACE1), sortilin-related receptor (SORL1), and MAPT. Each gene was thoroughly interrogated with tag single-nucleotide polymorphisms (SNPs), and gene-based tests were used to enhance power. We found no association of these genes with AD + P.