PLA2G6 and Parkinson disease: Pathogenic variants in PLA2G6 cause Phospholipase A2-associated neurodegeneration (PLAN) ‒ a disease spectrum ranging from a rapidly progressive and devastating form, infantile neuroaxonal dystrophy (INAD, MIM # 256600), to an atypical neuroaxonal dystrophy (ANAD, MIM # 610217), to young adult manifestations of parkinsonism with or without dystonia and other neurological symptoms.1