We measured plasma levels of amyloid β protein (Aβ) ending at positions 40 (Aβ40) and 42(43) [Aβ42(43)] in six carriers of βAPP717 (Val to Ile) mutation linked to familial Alzheimer's disease (FAD) as well as in patients with sporadic AD (sAD) and controls. The percentage and the level of Aβ42(43) were significantly higher in carriers of βAPP717 mutation relative to sAD, whereas Aβ40 levels were decreased. In contrast, Aβ levels and ratios were at similar levels in sAD, regardless of the stage of the disease, compared with non-AD neurologic disease controls and nondemented control individuals. These results suggest that the reported increase in the percentage of Aβ42(43) secretion in transfected cells with βAPP717 mutant genes actually takes place in the bodies of carriers of βAPP717 mutation, and that plasma Aβ could be used as an indicator of the alterations of βAPP/Aβ metabolism in subtypes of AD.
ASJC Scopus subject areas
- Clinical Neurology