Genetic findings have changed our views on Parkinson's disease (PD) and parkinsonism, which will be collectively referred to as Parkinsonian Syndrome (PS) in the present manuscript. Mutations in several genes are found to cause monogenic forms of the disorder. Point mutations, duplications and triplications in the alpha-synuclein gene cause a rare dominant form of PS in families. Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been identified as a much more common cause for dominant PS, especially in certain ethnic groups, while mutations in the parkin gene, in DJ-1, PINK1 and ATP13A2 cause autosomal recessive parkinsonism of early onset. The monogenic variants are important tools in identifying cellular pathways that also shed light on the molecular pathogenesis of sporadic PS and some of these genes may play a role in the etiology of the common sporadic form of PS. Here we add recent findings to a greatly challenging puzzle.