A dystonia characterized by segmental dystonia that predominantly affects the distal limbs and leads to abnormal posture. This disease has a progressive clinical course and may develop into generalized dystonia but remains mild overall. The disease is torsion dystonia 2 (MONDO_0009141). Also known as: DYT2, HPCA dystonic disorder, autosomal recessive torsion dystonia 2, dystonic disorder caused by mutation in HPCA, torsion dystonia type 2.