Dementia and Aging in Down Syndrome

Down syndrome (DS), usually the result of triplication of the 21st chromosome (trisomy 21), is the most common genetic cause of developmental and intellectual disability. With better health care, this population is surviving into older adulthood and experiencing many of the diseases associated with aging (cataracts, hearing loss, neck arthritis), but these diseases occur earlier in people with DS than in the general population. The most significant of these conditions is dementia, which is a brain-based deterioration of thinking ability and learning, personality, language, visual spatial skills, and functional capacity.

Dementia of the Alzheimer’s disease (AD) type is particularly prevalent in those with DS, with average onset in the early 50s and prevalence reaching 70% to 90% by the late 60s. This entry first discusses the ...