PRNP and Creutzfeldt Jacob disease: Together, the incubation time in tg650 mice and the brain PrPres profiles were unique among the panel of CJD cases transmitted so far to the tg650 line (Fig. 1 and unpublished data), thus fully supporting the contention that MM2-cortical CJD is a specific CJD subtype, as previously concluded from the absence of transmission to transgenic lines expressing physiological level of human PrP [10, 30, 40].