REDUCED TRANSFERRIN-BINDING IN DOWN-SYNDROME - A ROUTE OF SENILE PLAQUE-FORMATION AND DEMENTIA

PLASMA transferrin binding in Down syndrome and Alzheimer's disease is significantly reduced compared with age matched controls and it was t hought this may help elucidate a pathological time sequence for the on set of dementia in Down syndrome. In Down syndrome, there was a reduct ion in gallium and aluminium transferrin binding both with age and the onset of dementia. Nontransferrin bound gallium species were identifi ed as nontransportable phosphate or silicate. Thus, the route of entry of metals into the brain must be via a transferrin mediated complex o nly. A clear sequence of pathological events has been demonstrated in Down syndrome which shows the pathway to development of plaques and de mentia and this is believed to have an immunological origin.