THAP1 and torsion dystonia 6: Inherited isolated craniocervical dystonias are rare, and most commonly caused by pathogenic variants in THAP1 (Dystonia-6, DYT6, MIM# 602629) and GNAL (Dystonia-25, DYT25, MIM# 615073) and have adolescent to late adult onset with variable penetrance [2].