title: Iris pigmentation (melanin) in segmental dystonic syndromes including torticollis.
mesh_terms: D004421:Dystonia / Q000453:epidemiology / Q000378:metabolism*; D005006:Ethnicity; D005127:Eye Color; D006801:Humans; D008543:Melanins / Q000378:metabolism*; D044469:Racial Groups; D014103:Torticollis / Q000453:epidemiology
chemical_list: D008543:Melanins