Mutant gene responsible for FOP

From the Associated Press:

Scientists have discovered a mutant gene that triggers the body to form a second, renegade skeleton, solving the mystery of a rare disease called FOP that imprisons children in bone for life.

The finding, reported Sunday, may one day lead to development of a drug, not only to treat the rare bone disorder, but more common bone buildup related to head and spine trauma, and even sports injuries, the researchers said.

"We've reached the summit," said Dr. Frederick Kaplan, an orthopedist whose team at the University of Pennsylvania School of Medicine pinpointed the cause of FOP, or fibrodysplasia ossificans progressiva. The disease is believed to afflict only 2,500 people worldwide. ...

After 15 years of work involving study of the genetic makeup of multigenerational families around the world, scientists at Penn's Center for Research in FOP and Related Disorders found that FOP is caused by a single mutation in a gene called ACVR1. This devastating glitch means that tendons, ligaments and skeletal muscle begin painfully transforming into bone, sometimes locking joints overnight.

The genetic twist that leads to FOP, Kaplan said in a telephone interview, "is relevant to every condition that affects the formation of bone and every condition that affects the formation of the skeleton."