2013年9月9日訊 /生物谷BIOON/ --來自約翰霍普金斯大學醫學院和美國國家健康中心的研究人員最近發現了一種新的藥物成份能夠恢復唐氏綜合症小鼠的學習缺陷。唐氏綜合症又叫21三體綜合症，是由於細胞中出現3條21號染色體所致。一般患有這種症狀患者的身體症狀可以被緩解甚至治癒，但是目前還沒有有效方法來恢復患者的學習認知能力。這主要是因為這種疾病涉及到了太多的基因作用，而研究人員此次發現的有效成分能夠有效恢復小鼠的認知能力。（生物谷Bioon.com）
詳細英文報導：
Investigators at Johns Hopkins Medicine and the National Institutes of Health have discovered that a compound, when given as a single-dose treatment, radically boosts learning and memory in a mouse model of Down syndrome by growing the cerebellum of the rodents' brains.
Down syndrome occurs when people have three--rather than the normal two--copies of chromosome 21. Known as "trisomy," this means people with Down syndrome have extra copies of the more than 300 genes housed on that chromosome, which causes physical and mental disabilities.
Most physical manifestations of Down syndrome can now be treated, but there are no existing approved therapies to improve cognitive function in patients. One of the major hurdles to developing treatments is that the condition involves so many genes.
In mice genetically engineered to mimic Down syndrome, scientists used a sonic hedgehog pathway agonist to supercharge a biochemical chain of events known as the sonic hedgehog pathway that triggers growth and development. They injected the compound in the mice once at birth while the rodents' cerebellums were still developing.
"We were able to completely normalize growth of the cerebellum through adulthood with that single injection," said Roger Reeves, a professor in the McKusick-Nathans Institute of Genetic Medicine at the Johns Hopkins University School of Medicine.
What's more, the mice treated with the compound performed just as well in behavioral tests as normal mice. The findings appear in the Sept. 4 issue of Science Translational Medicine.
The researchers caution that use of the compound has not yet been tested and proven safe in humans with Down syndrome, but they hope their research spurs development of drugs like it.