PRKN and Parkinson disease: Chung et al. (2013) demonstrated that expression of TRAF6 in PD is inversely increased in human tissues when compared to Parkin. Parkin is responsible for the reduction of TRAF6 levels via proteasomal degradation and Chung et al. (2013) demonstrated that the loss-of-function Parkin mutations (R42P and T240R) did not result in decreased expression of TRAF6.