People with Down syndrome are prone to certain health conditions but researchers have long wondered why cancer is rarely one of them. Now, a study published in the journal Nature sheds light on the mysterious link between Down syndrome and cancer.

Down syndrome occurs when an extra copy of chromosome twenty-one is incorporated during conception. About one in every eight hundred babies is born with Down syndrome, and the risk of giving birth to a baby with this condition increases with age. People with Down syndrome typically experience learning disabilities, partial vision or hearing loss, and increased risk of heart disease. But their cancer rates are about ten percent lower than in the general population. The question is, why?

Renowned cancer researcher Judah Folkman suggested that people with Down syndrome are better able to prevent the formation of unnecessary blood vessels. People with Down syndrome rarely develop diseases like cancer and macular degeneration that thrive on the creation of extra blood vessels.

After Folkman died in 2008, other cancer researchers explored the theory further and discovered that two genes on the extra chromosome twenty-one seemed to suppress the cellular pathway that triggers the formation of new blood vessels.

Without new blood vessels, tumors can’t form and grow bigger. An extra copy of one of the genes did in fact suppress tumor growth in mice. Researchers hope the findings will lead to new cancer therapies… and when that happens, patients will have people with Down syndrome to thank.