MFN1 and Alzheimer disease: In AD, Aβ overproduction causes an imbalance in mitochondrial dynamics, affecting the levels of Drp1, Opa1, Mfn1 and 2, both in vitro and in postmortem brains of AD patients (Wang et al., 2008, 2009), inducing mitochondrial fragmentation and an abnormal distribution of mitochondria inside neurons.