PRNP and myopathy: Since myopathy has been described in GSS mice expressing the P102L allele (P101L in mouse PrP [32]), we sought these pathological changes in Tg.HRdup-26 animals with clinical disease; these studies failed to define necrotizing myopathy or neuropathy (S4 Fig), suggesting that these types of lesions do not contribute to the clinical presentation of Tg.HRdup mice.