General Information About Pycnodysostosis
Disease Details and Frequently Asked Questions
It is a rare genetic disorder where the continuous renewal (building and breaking down) cycle of the bones is disrupted; old bone cannot be absorbed and builds up. As a result, the bones become abnormally thick (dense) but break as easily as glass.
It is passed down in an autosomal recessive manner from parents due to a genetic mutation that prevents the production of 'Cathepsin K', an enzyme responsible for breaking down and absorbing old bone tissue.
Symptoms include pronounced short stature (dwarfism), delayed closure of the fontanelle, a prominent beak-like nose, dental eruption disorders, missing portions of the collarbones, and bones that fracture easily from minor trauma.
Diagnosis is guided by X-rays showing bones that have lost their hollow spongy inner structure, appearing completely white and chalk-like (osteosclerosis). The definitive diagnosis is made via a DNA test.
There is no treatment to repair the genetic mutation. Treatment focuses on protecting the patient from fractures and correcting the fractures that occur through orthopedic surgeries.
Our health library contents are prepared for informational purposes only and with scientific data available at the time of recording. For all your questions, concerns, diagnosis, or treatment regarding your health, please consult your doctor or a healthcare institution.



