Down syndrome (DS) can be considered as a form of genetically determined Alzheimer’s disease (AD) according to results from a cross-sectional study reported in the Lancet.
Adults with DS who had at least one AD biomarker were classified with the Cambridge Cognitive Examination for Older Adults with Down Syndrome (CAMCOG-DS). Cognitively healthy euploid controls (n=242) aged up to 75 years with no biomarker abnormalities were also included.
Of the participants with DS (n=388) 257 were asymptomatic, 48 had prodromal AD, and 83 had AD dementia. The order and timing of changes in biomarkers of AD was characterised.
Cerebrospinal fluid (CSF) levels of amyloid β (1-42/1-40) and neurofilament light chain (NFL) values changed in individuals with DS as early as the third decade. Amyloid PET uptake changed in the fourth decade, increasing about 12-15 years before expected symptom onset in the fifth decade.
In the seventh decade, symptomatic AD was present in 90-100 per cent of individuals. Symptomatic individuals showed increased global cerebral Aβ deposition compared to asymptomatic individuals.
The study shows that a substantial proportion of individuals with DS are capable and willing to do clinical trials and make an ideal population for preventative trials.