PRRT2 and epilepsy: Anecdotally, PRRT2 mutations have been described with other paroxysmal movement disorders, including paroxysmal torticollis of infancy (co-occurring with epilepsy in a patient with positive family history for PKD and HM) (36), intermittent non-epileptic head drops (again co-occurring with epilepsy) (30), and the “galloping tongue” syndrome (i.e., involuntary tongue movements only appearing upon tongue protrusion, which can be arguably deemed as a forme fruste of PKD) in a PRRT2 mutation carrier with a positive family history for PxD (37).