For Down Syndrome Adults, Death and Dementia Often Come Together

A study published in JAMA Neurology estimated that seven in 10 people with Down syndrome show evidence of dementia when they die, reports Medical Xpress . "Down syndrome is a genetic condition caused by having an extra copy of chromosome 21," says King's College London's Rosalyn Hithersay. "On this chromosome, there is a gene — the amyloid precursor protein, or APP gene — which controls the production of a protein called amyloid." The buildup of amyloid clumps in the brain is an established characteristic of Alzheimer's, with Hithersay noting, "All adults with Down syndrome will have lots of these plaques in their brain," even if not all go on to develop early dementia symptoms. The investigators tracked 211 Britons with Down syndrome who were 36 years and older. Nearly 33 percent were diagnosed with dementia prior to the study's launch, at an average age of almost 52. Over the 5.5-year study period, 70 percent of subjects with Down syndrome who died had dementia. The researchers calculated that persons with both Down syndrome and dementia were five times more likely to die early than those without dementia.