Abstract: The present invention provides DNA encoding a RIGUI protein selected from the group consisting of: (a) isolated DNA which encodes a RIGUI protein; (b) isolated DNA which hybridizes to isolated DNA of (a) above and which encodes a RIGUI protein; and (c) isolated DNA differing from the isolated DNAs of (a) and (b) above in codon sequence due to the degeneracy of the genetic code, and which encodes a RIGUI protein. Also provided is a vector capable of expressing the DNA adapted for expression in a recombinant cell and regulatory elements necessary for expression of the DNA in the cell. Further, a host cell transfected with the vector disclosed herein the vector expressing a RIGUI protein.

Abstract: The present invention provides a method of screening individuals at risk for developing diseases caused by trinucleotide repeat sequence instability. Specifically, the present invention is drawn to screening individuals at risk for developing autosomal dominant spinocerebellar ataxia type 6 by determining the length of a CAG trinucleotide repeat in the .alpha..sub.1A calcium channel gene of the individual. In addition, there is provided a method of identifying genes which are disease-causing due to trinucleotide repeat sequence instability by large scale genotyping.