Pycnodysostosis

**Definition:** Rare autosomal recessive syndrome characterized by delayed closing of CRANIAL SUTURES, short stature, ACRO-OSTEOLYSIS of distal phalanges, dental and MAXILLOFACIAL ABNORMALITIES and an increase in bone density that results in frequent BONE FRACTURES. It is associated with BONE RESORPTION defect due to mutations in the lysosomal cysteine protease CATHEPSIN K.

**Tree numbers:** - C05.116.099.708.779 - C16.320.565.595.800 - C16.320.812 - C18.452.648.595.800

**Synonyms:** - Pyknodysostosis