Fibrodysplasia Ossificans Progressiva is a disease where the body’s repair mechanism is broken. It starts malfunctioning and “repairing” the fibrous tissue (muscles, tendons and ligaments) by turning them into BONE. The entire body slowly begins to become petrified. Roughly 450+ people suffer from it and sadly there is no known cure(no clinical trials either). When trying to surgically remove the bone it results in more robust bone growth.
In one famous case a man survived up until the age of 40, but everything but his lips transformed into bone and he was unable to move.
Not all cases are this bad. I actually have this disease; it effects my maxilla bone. I have had surgery on it once already, and it has grown back. I will have to have it done again soon. =\