Genetic characterization of the ALFA study: Uncovering genetic profiles in the Alzheimer’s<i>continuum</i>

Abstract In 2013, the ALFA (ALzheimer and FAmilies) project was established to investigate pathophysiological changes in preclinical Alzheimer’s disease (AD), and to foster research on early detection and preventive interventions. Since then, it has prospectively followed cognitively unimpaired late/middle-aged participants, most of whom are adult children of AD patients. Risk stratification of cognitively unimpaired individuals, including genetic factors is key for implementing AD prevention strategies. Here, we report the genetic characterization of ALFA participants with respect to neurodegenerative/cerebrovascular diseases, AD biomarkers, brain endophenotypes, risk factors and aging biomarkers, emphasizing amyloid/tau status and gender differences. We additionally compared AD risk in ALFA to that across the full disease spectrum from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Results show that the ALFA project has been successful at establishing a cohort of cognitively unimpaired individuals at high genetic risk of AD. It is, therefore, well-suited to study early pathophysiological changes in the preclinical AD continuum . Highlights Prevalence of ε4 carriers in ALFA is higher than in the general European population. The ALFA study is highly enriched in AD genetic risk factors beyond APOE . AD genetic profiles in ALFA are similar to clinical groups along the continuum . ALFA has succeeded in establishing a cohort of CU individuals at high genetic AD risk. ALFA is well suited to study pathogenic events/early pathophysiological changes in AD.