THE GENE FOR SPINAL CEREBELLAR ATAXIA-1 (SCA1) IS FLANKED BY 2 CLOSELY LINKED HIGHLY POLYMORPHIC MICROSATELLITE LOCI

The gene for one form of autosomal dominant spinal cerebellar ataxia ( SCA1), is mapped by linkage to chromosome 6p, very close to the micros atellite locus D6S89. Eight large Italian kindreds segregating SCA1, a s defined by very close linkage to D6S89, were genotyped with five mic rosatellite markers linked closely to D6S89, all mapping within a 6 cM interval on 6p. Multipoint linkage analysis and haplotypes from recom binants map SCA1 between two of these markers, D6S274 and D6S259, 5 - 6 cM apart. A single rare four marker haplotype within this interval s hows linkage disequilibrium with the disease locus in southern Italy a nd is transmitted with SCA1 in five kindreds originating from this are a.