Although mentioned in most series, "pure" autosomal dominant cerebellar ataxias, except spinocerebellar ataxia type 6, are difficult to differentiate on clinical grounds.
UnIGENe, IBMC, Department of Neurology, Hospital de São Sebastião, Universidade do Porto, 4520-211 Santa Maria da Feira, Portugal. pcoutinho@hospitalfeira.min-saude.pt