Treatments for Down's syndrome are few and far between, with recent strategies tending to focus on slowing the progression of the genetic condition. Aricept, from Eisai and Pfizer, and Exelon, from Novartis Pharmaceuticals are examples.
The researchers found that people with Down's syndrome have higher levels of myo-inositol in patient's brains They discovered that increased levels of this molecule are associated with reduced intellectual ability.
The researchers also suspect that high levels of myo-inositol could play a role in predisposing people with Down syndrome to early-onset Alzheimer's disease.
Myo-inositol is known to promote the formation of amyloid plaques in the brain (a hallmark of Alzheimer's disease), and all people with Down's syndrome also develop these plaques in later life.
However, not all people with Down's syndrome will go on to develop dementia, and its incidence is no higher than in the general population.
Similarities between the two conditions have led to much of our current understanding. Many individuals with Down's syndrome eventually will develop Alzheimer's disease after the age of 40, according to Down's syndrome researchers.
In both conditions, people don't produce enough of a chemical called acetylcholine in the brain, which results in learning and memory problems.
Thus, the theory goes, treatments that work on Alzheimer's may also be beneficial with Down's syndrome.
"We have shown in this study that adults with Down's syndrome have a significantly higher concentration of myo-inositol in the hippocampal region of their brains, and this increase is associated with a reduced cognitive ability," commented lead researcher, Professor Declan Murphy.
"We are now carrying out more studies to see if we can reduce the concentration of myo-inositol in the brains of people with Down's."
In a statement, The Down's Syndrome Association welcomed any research that would have a beneficial effect on the lives of people with Down's syndrome.
"We are very pleased that scientists are producing results that help us to understand the reasons behind Down's syndrome's associated learning disability. However, the Institute of Psychiatry's research does not herald a 'cure' for the condition, and any treatment available is still a long way in the future," they added.
Pharmaceutical companies said that Alzheimer's is still their key market, although the potential for expanded use is gaining attention in the industry.
A growing body of literature suggests that Alzheimer's drugs may work on other developmental disabilities, such as autism.
Aricept, Exelon and a third Alzheimer's drug, Reminyl from Ortho-McNeil, a subsidiary of Johnson & Johnson, also have been tested in autistic individuals.
The study is published in Archives of General Psychiatry.