Neuropathology of Case 1. The neuropathological analysis showed the presence of severe neuronal loss and spongiform changes in the cerebral cortex (a: frontal cortex, Haematoxylin-Eosin), associated with astrogliosis (b: frontal cortex, GFAP immunostaining). The pattern of PrPSc deposition was defined by diffuse, finely granular synaptic-like immunoreactivity (c: 3F4 immunostaining, frontal cortex). In the cerebellum, loss of Purkinje and very mild spongiosis in the molecular layer (d: Haematoxylin-Eosin), astrogliosis (e: GFAP immunostaining) and PrP build up were present: finely granular PrP deposits in the molecular layer and coarser spots in the granular layer (f: 3F4 immunostaining). The PrP deposits were not fluorescent after thioflavin S (not shown). Scale bars: in (a) = 100 μm (a, b, d and f are the same magnification); in (c) = 50 μm (c and e are the same magnification).