Pantothenate kinase-associated neurodegeneration (formerly called Hallervorden-Spatz syndrome) is a disorder of the nervous system. The condition is characterized by progressive difficulty with movement and speech. Affected people may also experience loss of intellectual function (dementia) and problems with vision. Researchers have described classic and atypical forms of pantothenate kinase-associated neurodegeneration. Both types involve a buildup of iron in certain parts of the brain. The pattern of signs and symptoms varies between the two types, however. The classic form appears earlier in childhood and progresses more rapidly than the atypical form.