A new study by researchers from the Sanford-Burnham Medical Research Institute revealed the mechanism behind the theory that people with Down syndrome are at high risk for Alzheimer 's disease. They found out that nearly 100% of people with Down's syndrome, when they reach the age of 40, will most likely develop brain changes that can lead to dementia.
Down syndrome is the most common genetic or chromosomal abnormality in humans. They have an extra coop of chromosome 21. That is why it is also termed as Trisomy 21. Past studies have determined that people with this chromosomal abnormality are at high risk for dementia particularly Alzheimer's. In fact, at about 35 years old, 25% will already manifest symtoms of dementia while at age 65, 75% of them will manifest symptoms of dementia.
The researchers conducted a study on mice. They found out that mice who have signs of Down syndrome as well as people with diagnosed case of Down's syndrome have low levels of sorting nexin 27 (SNX27), a type of protein.
What is SNX27? This type of protein is important in the maintenance of brain surfaces. They are vital in order for neurons to work properly. Lowered levels of this protein can lead to impaired neuron activities.
Furthermore, they regulate the production of beta-amyloid which is the protein toxic to neurons. This is a sticky protein wherein they stick to dead neurons and form plaques in the brain. Plaques, as many know, are the reason why Alzheimer's disease develops.
The team's next step is to properly diagnose the problem and develop strategies that might help individuals with Down syndrome to be able to live longer without dementia. Dr. Huaxi Hu, lead researcher said that they have defined a complex mechanism that explains how low levels of SNX27 can lead to boost in the production beta-amyloids.
Down syndrome and Alzheimer's disease are two predicaments and conditions that are not really well-explained.