Neuroacanthocytosis Syndromes II

The differential diagnosis of a neurological patient presenting with chorea is difficult. Huntington disease (HD) is best known and can be readily established with genetic testing should clinical features not be clear. But, if not HD, there are many possibilities. These include Huntington disease-like 1 (HDL1), Huntington disease-like 2 (HDL2), chorea-acanthocytosis (ChAc), McLeod syndrome (MLS), benign hereditary chorea types 1 and 2 (BHC), familial dyskinesia and facial myokymia, pantothenate kinase-associated neurodegeneration (PKAN), neurof- ritinopathy, dentatorubral-pallidoluysian atrophy (DRPLA), and spinocerebellar ataxia 17 (SCA17). All these disorders are relatively uncommon, but there are ways of making the diagnosis and the hard part is keeping them in mind. A subset of these choreas is also characterized by the presence of acanthocytes in the blood, and this fact is valuable from a diagnostic point of view, but is also an interesting cli- cal clue in regard to the pathophysiology. ChAc and MLS have many acanthocytes, and HDL2 and PKAN may have acanthocytes. The acanthocytes are a reminder that the manifestations of these disorders are broad and include a range of neu- logic symptoms and systemic abnormalities. Since there is only little research on these entities, it is valuable to make a periodic synthesis of the state of the art, to draw people’s attention to the area, and to stimulate further research. A first book on the neuroacanthocytosis syndromes came from the first international conference in 2002.