Alzheimer’s disease causes progressive and irreversible damage to the brain, and is the most common form of dementia. Symptoms of Alzheimer’s include memory loss followed by general impairment of mental functions and disordered behaviour. This disease, in the United States alone, has affected over 4.5 million people and the occurrence of this is expected to double within the next 25 years. US scientists identified the first gene marker of late-onset Alzheimer’s in 1993, and within two years Canadian researchers had connected two genes to the aggressive early-onset form.
Last year, US and Canadian researchers identified another gene marker believed responsible for the most common late-onset of Alzheimer’s.
“The importance of the finding is that it opens new pathways to explore the cause of the disease, as well as potential targets for treatment.”
Richard Mayeux of Columbia University’s Taub Institute for Research on Alzheimer’s Disease and the Ageing Brain, and one of the authors of this study.
Researchers conducted genetic studies, involving over 6 000 volunteers, in which they discovered that variants of the SORL1 gene were much more common in people with late-onset of Alzheimer’s than healthy people of the same age. Also, it was shown that Alzheimer sufferers had as much as 50 per cent less of the proteins produced by the SORL1 gene in their blood than of healthy people the same age.
“SORL1 is another critical piece of the Alzheimer’s disease puzzle.”
Richard Mayeux
The SORL1 gene regulates the flow of amyloid precursor protein (APP) inside the nerve cells of the brain. In healthy people, SORL1 sends APP to a part of the brain where it is recycled. It was discovered that in the people who had the gene variant, the protein produced by the SORL1 gene appears to drive the APP to another region of the cell where it accumulates and is degraded into amyloid plaques. These plaques are abnormal sticky proteins that build up in the brain of Alzheimer’s victims causing the symptoms to persist and even worsen.
In today’s times, effective drugs and treatments for this disease are still lacking and development of these effective methods to combat Alzheimer’s still on the drawing board as the only definitive way to diagnose the illness is by autopsy. Because of this, the value of screening people for the disease is questionable as nothing much can be done about it. Through the discovery of effective therapies that could prevent brain damage and even Alzheimer’s disease from occurring, then all this changes.
Reference:
France-Presse, A. 15th January, 2007. “Gene for Alzheimer’s Discovered” viewed 27th March, 2009. http://www.cosmosmagazine.com/news/964/gene-alzheimers-discovered
(image from same website)
Submitted by: s4201727
