Five families with late onset spinocerebellar ataxia (SCA) were studied. A high association was found between the disease and HLA. A stronger association results with a marker called D6S89. Clinical data of 26 patients and neuropathological study in two are reported. The clinical phenotypes of other HLA-linked SCA kindreds shows differences when comparison is made. The Authors suggest that the phenotype might appear more homogeneous if disease duration is taken into account.