Alpha synuclein is a member of the synuclein family, the other two proteins being beta and gamma synuclein. Alpha synuclein was originally isolated as a major synaptic vesicle associated protein from the electric organ of the fish Torpedo (1). Direct homologs of alpha-synuclein are found in all vertebrates. Later work connected alpha-synuclein with human brain pathology, when a protein originally identified as a component of NAC, the "Non-Amyloid beta Component of Alzheimer's disease amyloid" proved to be a peptide derived from alpha-synuclein (2). The alpha-synuclein protein is therefore sometimes known as NAC precursor or NACP. Further work showed that alpha-synuclein is a major component of the Lewy bodies of Parkinson's disease and point mutations of alpha-synuclein proved to be causative of some forms of familial Parkinson's disease (3, 4, 5). Early onset Parkinson's disease may be caused by a duplication or triplication of one of the Alphasynuclein genes (6, 7). However, despite being discovered as as component of amyloid preparations, alpha-synuclein is apparently not a major component of the senile plaques of Alzheimer's disease (6). Early onset Parkinson's disease may be caused by a duplication or triplication of one of the alpha synuclein genes (7, 8). Alpha-synuclein is also found in the Lewy bodies of patients with diffuse Lewy body disease and inclusions in glial cells in the brains of patients with multiple system atrophy (MSA) and amyotrophic lateral sclerosis (ALS). Alpha-synuclein is heavily expressed in brain and appears to be localized primarily to presynaptic regions, though not with a typical synaptic vesicle distribution pattern. The synuclein proteins appear to have little 3D structure in solution, and probably belong to the family of "intrinsically unstructured proteins" which only adopt a well-defined conformation when bound to other proteins or membrane lipids (9). An excellent recent review of the role of alpha-synuclein in health and disease was recently published by Mark Cookson (10). The HGNC name for this protein is SNCA.