Distal clavicle defect

Pycnodysostosis (from Greek: πυκνός (puknos) meaning "dense", dys ("defective"), and ostosis ("condition of the bone")), is a lysosomal storage disease of the bone caused by a mutation in the gene that codes the enzyme cathepsin K. Signs and symptoms Pycnodysostosis causes the bones to be abnormally dense (osteopetrosis); the last bones of the fingers (the distal phalanges) to be unusually short; and delays the normal closure of the connections (sutures) of the skull bones in infancy, so that the "soft spot" (fontanelle) on top of the head remains widely open.Those with the syndrome have brittle bones which easily break, especially in the legs and feet. The jaw and collar bone (clavicle) are also particularly prone to fractures. [Source: Wikipedia ]