Among SNCA-linked diseases and disorders, PD, Alzheimer’s disease (AD), tauopathy, degenerative dementia, progressive motor neuropathy, familial encephalopathy, hereditary and motor neuropathies, a disorder of basal ganglia, movement disorders, neuromuscular diseases, and other progressive neurological diseases were found to be the major diseases and disorders linked to SNCA gene. Here, SNCA is linked to early-onset autosomal dominant Alzheimer disease.