UAS regulates expression of the DNA sequence covering exon 40 to the 3' end of the bicistronic Hsap\CACNA1A gene (i.e. the 'α1ACT' product) containing 33 CAG/Q repeats. (The normal non-pathogenic number of repeats is 11Q, while Spinocerebellar ataxia type 6 (SCA6) results from a polyQ tract of 19-33 in patients.)