Down’s syndrome: compound reverses deficits Study published in “Science Translational Medicine”
American researchers have identified a compound that dramatically improves memory and learning in mice with Down’s syndrome, reports a study published in “Science Translational Medicine.” “The majority of people with Down’s syndrome have an area of their brain -- the cerebellum -- that is 60% smaller than normal,” stated one of the study’s authors, Roger Reeves, in a press release. “We treated rats with Down’s syndrome using a compound that we thought would normalize the cerebellum’s growth, and, in fact, it worked perfectly. What surprised us were its effects on learning and memory, which are typically controlled by the hippocampus rather than the cerebellum,” the researcher added. Researchers at Johns Hopkins and the National Institutes of Health in the United States explain that Down’s syndrome occurs when people have three rather than two copies of chromosome 21. As a result of such trisomy, the affected individuals have extra copies in nearly half of the genes found on this chromosome. This study used mice with characteristics similar to the individuals with Down’s syndrome, including a relatively small cerebellum as well as difficulties learning and remembering how to navigate through a familiar environment.

Researchers focused on a biochemical path, sonic hedgehog, which is involved in brain growth and development. A compound capable of activating this path was injected only on the day the animals were born, while the cerebellum was still under development. “We were able to normalize the growth of the cerebellum up to adult age with a single injection,” said Reeves. The research also determined that mice treated with the compound presented capacities similar to healthy animals with respect to orientation in space. The study’s authors caution that this compound is not yet secure for use in individuals with Down’s syndrome. In fact, the change of this very important path may affect the entire organism, such as the increased risk of cancer through inappropriate growth. Researchers are now focusing on this strategy’s potential while studying more secure ways of leveraging the power of this path in the cerebellum.