Diffuse Plaques in the Cerebellum and Corpus Striatum in Down's Syndrome Contain Amyloid β Protein (Aβ) only in the Form of Aβ42(43)

The diffuse amyloid (Aβ) plaques of the cerebellum and corpus striatum were examined in 32 patients with Down's syndrome, ranging in age from 9 to 71 years, using the end-specific monoclonal antibodies BA27 and BC05 to detect Aβ species terminating at amino acids 40 and 42(43) respectively. When present, the diffuse plaques of both regions contained only Aβ₄₂₍₄₃₎at all ages. Aβ₄₀was, however, present along with Aβ₄₂₍₄₃₎in the few cored plaques that were occasionally present in the Purkinje and molecular cell layers of the cerebellum of some of the more elderly patients. It is concluded that diffuse plaques of the cerebellum and striatum contain only Aβ₄₂₍₄₃₎and that, in contrast to those of the cerebral cortex, these do not ‘mature’ during their lifetime into Aβ₄₀containing plaques.