ABSTRACT
This chapter reviews the influence of genetic factors on risk of dementia in Alzheimer’s disease (DAD) among adults with Down syndrome (DS). It discusses genetic factors that may increase Aß deposition, genes located on chromosome 21 that are over expressed and implicated in AD pathogenesis, and factors associated with accelerated ageing and early mortality in individuals with DS. Ageing of adults with DS has recently become an issue of great concern because of the high risk of Alzheimer's disease (AD) in this rapidly growing population. Virtually all adults with DS over 35 to 40 years of age exhibit many of the key features of AD neuropathology, and many of these individuals will develop dementia by the time they reach 60 to 70 years of age. AD is the commonest cause of dementia among older people, and affects parts of the brain that control thought, memory and language abilities, resulting in progressive decline.
