PRNP and nervous system disorder: Tg(PrP-A116V) mice, which express mouse PrP-A116V (the human homologue of PrP-A117V in GSS) at levels 4–6 times higher than PrPC in WT mice, also spontaneously developed neurological disease around 150 days after birth, with spongiosis and PrP amyloid plaques in their brains (Table 1) [59].