PLA2G6 and Parkinson disease: PLAN encompasses a continuum of three overlapping phenotypes: 1) infantile onset PLAN, corresponding to classic infantile neuroaxonal dystrophy, 2) childhood-onset PLAN corresponding to atypical neuroaxonal dystrophy (ANAD) and 3) juvenile adult-onset PLAN corresponding to PLA2G6-related dystonia-parkinsonism. These patient exhibit predominantly HRS, resting tremor and limbs, oromandibular or generalized dystonia