A Link Between Down Syndrome And Alzheimer’s
First Published: Investigator - February 2009
A group of scientists based at Flinders Medical Centre are investigating a protein that is over-expressed in both Down syndrome and Alzheimer’s disease with the intent of identifying if there is a common link between these two conditions.
“Down syndrome is a genetically-based disorder which results in multiple conditions for sufferers,” said Dr Damien Keating, Head of the Molecular and Cellular Neuroscience Lab.
“Amongst these conditions, Down syndrome individuals normally develop Alzheimer's disease at an early age, often as young as their mid 30s or early 40s.”
Those born with Down syndrome have a trisomy (three copies) of the human chromosome 21 rather than the normal two.
This means that every cell in the body has an extra copy of the genes that make up chromosome 21, which leads to the symptoms and physical characteristics associated with Down syndrome.
One of the proteins that make up chromosome 21, called RCAN1, is over expressed in neurons in the brain of those with both Down syndrome and Alzheimer’s disease. Dr Keating has found that RCAN1 works as a regulator of a process called exocytosis which controls the firing of messages from one neuron to another (neurotransmission) in the brain.
Dr Keating’s lab, which is a leader in measuring cell signalling, has been testing different levels of RCAN1 expression and has discovered that both under and over expression of the protein reduces this neurotransmission.
This reduction of neurotransmission causes brain function and performance problems and can lead to brain cell death, as is often seen in both Down syndrome and Alzheimer’s.
“We hope to understand why changing the normal expression of RCAN1 affects neuron function and communication, to better understand what happens in the brain in conditions where RCAN1 levels are increased." said Dr Keating.
“For example, could the risk of Alzheimer’s and the effects of Down syndrome be reduced by normalising the expression of RCAN1?”
Dr Keating and his team continue their investigations in the hopes of contributing to a better understanding of these conditions.