PRNP and Ataxia: We found that Tg9949 mice are significantly more likely to develop ataxia than wt FVB mice (n = 12; p = 0.03) and Tg mice that express full-length PrP at 4–8 times wt levels (Tg4053 mice, n = 62; p<0.001) [17],[27],[28].