The transmissible brain amyloidoses: a comparison with the non transmissible brain amyloidoses of Alzheimer type.

I report here the basic concepts of the transmissible and non-transmissible cerebral amyloidoses. The pathogenesis of both types of brain amyloidoses consist of a synthesis of amyloid precursor followed by its processing to yield a final postranslationally modified deposit. PrPc and APP serve as precursor proteins while modified PrP (PrPsc and PrP 27-30) and beta-A4 as final deposits in transmissible and non-transmissible brain amyloidoses, respectively. The hallmark of both types of brain amyloidoses is amyloid deposits immunoreactive to appropriate amyloids. Other, mostly unspecific, neuropathological phenomena as neurofibrillary tangles, dystrophic neurites and granulovacuolar degeneration are also discussed. The only disease-specific structure for transmissible cerebral amyloidoses are tubulovesicular structures of unknown biological significance. They may even be the infectious virus.