Disease of infancy or early childhood in which bones do not properly ossify, or harden. Weight-bearing bones of the body become deformed. the legs become bent. Sternum projects forward and bony nodules form on the ends of ribs, and at wrists, ankles, and knees. Skull is large and square. Pelvic opening in a girl may narrow, leading to problems with childbirth later. Other symptoms: flaccid muscles, delayed teething, potbelly.