Fibrodysplasia ossificans progressiva is a heritable and generalized disorder of connective tissue, characterized by the appearance of bony tissue within the striated muscles, tendons and ligaments; moreover, some skeletal abnormalities may also occur, mainly microdactyly of the big toes. This is a very rare disease, which presents in early life; its course is unavoidably progressive, producing a sort of petrifaction of the patient some years after the first symptoms. It is defined as an autosomal dominant trait, being due in most cases to a new mutation. At present no known treatment is available to stop the course of the disease, but sometimes disodium etidronate may be effective in preventing calcification of heterotopic bony tissue.