The transgene was engineered from BAC DRPLA18E that contains the human gene for ATN1 from a patient with dentatorubral-pallidoluysian atrophy (DRPLA) with a 76 CAG trinucleotide repeat within the gene. Three lines were created (lines Drm12, Drm21, and Drm22) with 78, 76 and 77 CAG repeats, respectively.