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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Adult, Age Factors, Aged, Aged, 80 and over, Alzheimer Disease, Amyloid beta-Peptides, Apolipoprotein E4, Enzyme-Linked Immunosorbent Assay, Family Health, Female, Humans, Male, Middle Aged, Peptide Fragments, Polymorphism, Genetic, Presenilins, Psychiatric Status Rating Scales, Sex Factors, Time Factors.
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Is plasma amyloid beta protein elevated in late-onset Alzheimer disease families? Context: Plasma A beta levels are elevated in early-onset Alzheimer disease (AD) caused by autosomal dominant mutations. Our objective was to determine whether similar genetic elevations exist in late-onset AD (LOAD). We measured plasma A beta in first-degree relatives of patients with LOAD in a cross-sectional series and in extended LOAD families. We screened these subjects for pathogenic mutations in early-onset AD genes and determined their ApoE genotypes. Plasma A beta is significantly elevated in the LOAD first-degree relatives in comparison to unrelated controls and married-in spouses. These elevations are not due to ApoE epsilon 4 or pathogenic coding mutations in the known early-onset AD genes.
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The findings provide strong evidence for the existence of novel, as yet unknown genetic factors that affect late-onset Alzheimer disease by increasing A beta. Final Decision: yes