ABSTRACT
An association between Down syndrome (DS) and dementia was first noted by Fraser and Mitchell in 1876, who wrote that in not a few instances, however, death was attributed to nothing more than a general decay a sort of precipitated senility. Senile plaques (SP) and neurofibrillary tangles (NFT) in individuals with DS generally resemble those seen in Alzheimer’s disease (AD) at both light and electron microscope levels. The cerebral atrophy that is characteristic of AD results from the progressive effects of a pathological cascade process that ultimately leads to a shrinkage and loss of nerve cells in particular cerebral cortical and subcortical regions, and the loss of pathways connecting such areas. Serial computerised tomography (CT) scanning also shows that while healthy young people with DS have smaller brains than individuals of the same age within the general population, older subjects with DS have a reduced brain size which declines further with age and upon the onset of dementia.
