Alzheimer’s disease (AD) is the most common cause of dementia in individuals over the age of 65. Brains of people with AD frequently exhibit features due to abnormal protein deposition. It has been shown that the ε4 allele of the APOE gene and the R47H variant of TREM2 increase the risk of AD. On the other hand, Down Syndrome (DS) is the most frequent genetic form of intellectual disability. Life expectancy of individuals with DS is currently 60 years. Starting at age 40, people with DS have an increased risk of dementia and almost all of them have histopathological features of AD in their brains. Since there is not much information on biomarkers and genetic risk factors of dementia in DS, we proposed to analyze them.
Sixteen participants with DS were recruited Cognitive status was assessed by clinical and neuropsychological evaluations. Also, participants underwent positron emission tomography to evaluate global cerebral metabolism (FDG) and cerebral Aβ (PiB), respectively. AD risk variants in APOE and TREM2 were analyzed by RFLP-PCR.
Ten participants exhibited the 3/3 genotype in APOE, four the 3/4, and two had the 2/3. We found a trend towards a greater presence of the risk allele ε4 in participants with cognitive impairment. In agreement with its low population frequency, we did not observe the R47H risk variant in this group.
Overall, data obtained here set the ground for further investigations on factors modulating dementia onset in adults with DS in our population