The patients and controls in two of the cohorts were age-matched, while the patients with Alzheimer’s disease were significantly older than the controls in the Swedish cohort I. However, no statistically significant correlations between age and levels of the tryptic peptides of SNAP-25 (Ac-2-16, 17-31, and 32-40) in either the control group or the Alzheimer’s disease group were observed, suggesting that the detected SNAP-25 fragments not are influenced by age. The gene discussed is SNAP25; the disease is early-onset autosomal dominant Alzheimer disease.