Genes and molecules
Much of our understanding of Alzheimer’s and other dementias comes from studying genes and molecules like proteins. They may be a million times smaller than the head of a pin, but they are the building blocks of our bodies and even the smallest change in them can have big knock-on effects on how our bodies work.
During Alzheimer’s a protein called amyloid builds up and forms sticky clumps, or ‘plaques’ between nerve cells in the brain. Inside nerve cells a different protein, tau, becomes tangled up. These proteins normally perform important functions in our brains, but during Alzheimer’s they change and damage cells. Many researchers are now designing treatments to stop these proteins building up and to protect nerve cells from harm.
The human genetic code is made up of over three billion letters and contains more than 22,000 genes. Huge advances in technology have made it 10,000 times cheaper to sequence this code than it was a decade ago, allowing scientists to unravel the biology of diseases that cause dementia. Several genetic mutations have been found to cause rare inherited forms of Alzheimer’s and frontotemporal dementia, many of which alter the production of the amyloid and tau proteins.
Researchers are also comparing the DNA code of thousands of people with and without dementia to look for natural variations in our genes that are more common in those with the condition. Recent studies identified more than 10 genes with variants linked to an increased risk of Alzheimer’s. These variants are common and often only have a small effect on risk, but identifying them can revolutionise our understanding of Alzheimer’s by linking new biological processes to the disease. Researchers are now searching for more genetic variants, to unlock more clues.
By uncovering these minute details and finding the molecules involved in these processes we are building an ever clearer picture of what causes dementia. Understanding the causes can uncover places for potential treatments to act.
THIS IS THE STRUCTURE OF THE AMYLOID PRECURSOR PROTEIN, WHICH IS CHOPPED UP IN THE BODY TO MAKE AMYLOID.