The protein encoded by this gene is highly homologous to alpha-synuclein. These proteins are abundantly expressed in the brain and putatively inhibit phospholipase D2 selectively. The encoded protein, which may play a role in neuronal plasticity, is abundant in neurofibrillary lesions of patients with Alzheimer disease. This protein has been shown to be highly expressed in the substantia nigra of the brain, a region of neuronal degeneration in patients with Parkinson disease; however, no direct relation to Parkinson disease has been established. Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Jul 2008].