Lower functional connectivity of default mode network in cognitively normal young adults with mutation of APP, presenilins and APOE ε4

In this study, we used resting-state functional magnetic resonance imaging to explore the genetic effects of amyloid precursor protein (APP) or presenilins mutation and apolipoprotein E (APOE) epsilon 4 on the default-mode network (DMN) in cognitively intact young adults (24.1 +/- 2.5 years). Both the APP or presenilin-1/2 group and the APOE epsilon 4 group had significantly lower DMN functional connectivity (FC) in the some brain regions like precuneus/middle cingulate cortices (PCu/MCC) than controls (AlphaSim corrected, P < 0.05). Only a lower FC tendency was demonstrated (control < APOE epsilon 4 < APP or presenilin-1/2 group). Moreover, lower FC in PCu/MCC is correlated with some neuropsychological assessments such as similarity test in APOE epsilon 4 group. These findings indicate that DMN FC alteration in APP or presenilin-1/2 or APOE epsilon 4 subjects is prior to the occurrence of neurological alterations and clinical symptoms, and DMN FC might be a valuable biomarker to detect genetic risk in the preclinical stage.