Did You Know!
A Rare Genetic Disorder Slowly Turns Muscle Into Bone
One of the rarest genetic disorders in the world is Fibrodysplasia Ossificans Progressiva (FOP), sometimes called “stone man syndrome.” People born with this condition gradually develop bone inside muscles, tendons, and ligaments, creating what doctors call a “second skeleton.”
The disorder is caused by a mutation in the ACVR1 gene, which normally helps regulate bone growth. In people with FOP, even minor injuries, injections, muscle strains, or falls can trigger the body to form new bone where it doesn’t belong.
Over time, joints become permanently locked as muscles harden into bone, severely limiting movement. One unusual clue appears at birth: most babies with FOP are born with malformed big toes, which can help doctors recognize the condition early. Because surgery usually causes even more abnormal bone growth, treatment focuses on preventing injuries and managing symptoms rather than removing the extra bone.
