There is a disease in which the development of all tissues are replaced with bone

Fibrodisplations ossificans progressiva - a condition in which muscle tissue, tendons and ligaments are gradually replaced by bone. Okostenivanie begins with a neck shoulder, gradually spreading throughout the body.

It is possible that references to people, "turned to stone", which are often found in the folklore and mythology, obyanyayutsya exactly this phenomenon. Fibrodisplations manifested in the formation of inflammatory processes in tendons, ligaments, fascia, subcutaneous tissues and muscles, which eventually leads to calcification and ossification. The disease is also called the "disease of the second skeleton," as where the body should be established inflammatory processes, bone growth begins.

Fortunately, the disease is very rare, they suffer only 1 person on 2000 000.

via factroom.ru