More than one-quarter of people with Down syndrome will be alive at age 67. As they live longer, improving their quality of life and maximizing their abilities is of paramount importance, Kishnani said. The brains of both Alzheimer's disease and Down syndrome patients do not produce enough of a chemical known as acetylcholine. This malady occurs much earlier in people with Down syndrome. In fact, individuals with Down syndrome develop Alzheimer's disease at a much earlier age, usually in the fourth decade, compared to the general population.
Acetylcholine carries signals from one neuron to another.
There, the signal connects in a process akin to turning on a lamp by plugging it in. But if there isn't enough acetylcholine available to a nerve cell to allow it to pass a signal on, a person will experience problems with learning and memory, among other deficits. Trials of the drug in Alzheimer's disease patients have shown that donepezil improves overall functioning and cognition, which can result in improved use of language and behavior. It is also less toxic than tacrine, an earlier type of cholinesterase inhibitor and the only other approved drug to treat Alzheimer's. In testing donezil's ability to help Down syndrome, Kishnani enrolled three men and one woman, age 27 to 64, as well as their primary caregivers.