Spinocerebellar ataxia: multipoint linkage analysis of genes associated with the disease locus.

Spinocerebellar ataxia (SCA) was studied in a seven-generation (Schut-Swier) kindred using linkage analysis to localize further the autosomal dominant, HLA-linked, disease-producing SCA1 locus relative to four other loci that map to the short arm of human chromosome 6. Genotypes for each locus were determined in as many individuals as possible from a total of 162 affected and unaffected family members that were studied. A maximum pairwise lod score of 8.52 (theta m = 0.10, theta f = 0.22) for linkage between SCA1 and HLA-A was observed. Multipoint linkage analyses for the SCA1, HLA-A, F13A, D6S7, and GLO1 loci revealed that the SCA1 locus is most probably located telomeric to HLA-A, with a likely location between HLA-A and F13A.