Rare genetic dystonia Limb dystonia true OMIM:611284 ICD10:G24.8 orphanet Focal limb dystonia is a form of focal dystonia (see this term), characterized by dystonic spasms of arm or leg muscles accompanied by repetitive, twisting movements or abnormal positions or postures. Limb dystonia may also be segmental, that is affecting group of muscles of an arm as well as the neck, and is also present in those with hemidystonia or generalized dystonia.