First, a genetic link was found to associate a-syn to Parkinson’ disease; the point mutation in SNCA (A53T) was demonstrated to cause autosomal dominant Parkinson’s disease [126] and several other point mutations (A30P, E46K, H50Q, G51D and A53E) have since been shown to cause familial forms of Parkinson’s disease and dementia with Lewy bodies (DLB) [4, 79, 84, 119, 129, 167]. Here, SNCA is linked to Parkinson disease.