May regulate the subcellular localization of CIP/WAF1. Interacts with CIP/WAF1. Defects in CIZ1 may be a cause of adult onset primary cervical dystonia. Dystonia is defined by the presence of sustained involuntary muscle contractions, often leading to abnormal postures. Cervical dystonia or spasmodic torticollis, the most common form of focal dystonia, is characterized by involuntary contractions of the neck muscles, which produce abnormal posturing of the head upon the trunk. Truncated N-terminus. Truncated N-terminus.