MAPT and early-onset autosomal dominant Alzheimer disease: This gene may serve to integrate presynaptic signaling and membrane trafficking, in particular in the regulation of dopamine release and transport. It reduces neuronal responsiveness to various apoptotic stimuli. It has been found that SNCA peptides are a major component of amyloid plaques in the brains of patients with Alzheimer's disease. Also, it seems involved in the fibrillization of microtubule-associated protein Tau.