HLA--determination in families with hereditary ataxia.

In three families with hereditary ataxia, where the inheritance pattern was autosomal and dominant, HLA antigens were determined in 25 members. In two of the families, HLA linkage of disease was suggested, whereas in the third family, the data did not directly support this concept, since two recombinational events between the postulated locus for disease and the HLA region had to be assumed. However, with this assumption, our data are compatible with those of one family described recently (Jackson et al. 1977) implying the presence on the sixth chromosome, outside the HLA region, of a locus that determines the development of spino cerebellar ataxia (SCA). Further tests with definition of enzyme markers will have to be performed before conclusions as to HLA linkage of a postulated SCA gene can be made.