POLYMERASE CHAIN-REACTION QUANTIFICATION OF LYMPHOID AMYLOID PRECURSOR PROTEIN MESSENGER-RNAS IN ALZHEIMERS-DISEASE AND DOWNS-SYNDROME

Amyloid beta-protein, the major constituent of Alzheimer's disease (AD ) brain amyloid deposits, is encoded by several alternatively spliced amyloid precursor protein (APP) mRNAs. The well-established associatio n in Down's syndrome (DS) between APP overproduction and premature dev elopment of AD, as well as the recent demonstration of an increase in APP transcripts from lymphoblastoid cells of familial AD cases, sugges t aberrant transcriptional regulation of some genes in AD, We assayed steady-state expression of the APP gene transcripts in peripheral bloo d mononuclear cells (PBMC) of AD and DS patients using quantitative po lymerase chain reaction of reverse-transcribed mRNAs, and we compared their levels of PBMC APP expression with those of young and age-matche d healthy controls. Results indicate APP mRNAs were of comparable abun dance in PBMC obtained from 9 AD patients, 6 DS patients, 7 young cont rols and 12 age-matched controls. These data suggest regulation of APP mRNAs is normal in AD and DS PBMC.