PARK7 and Parkinson disease: Monogenic forms of PD have been linked to loss-of-function mutations in a number of genes, giving rise to autosomal recessive parkinsonism [15], including mutations in parkin, which encodes an E3 ligase, and in DJ-1, which encodes a putative redox sensor that associates with chaperones [16] and translocates to mitochondria during conditions of oxidative stress [17-22].