both pycnodysostosis and osteoporosis cause brittle bones. however pycnodysostosis is a disease with abnormally dense bones whereas osteoporosis is exactly the opposite a disease with washed-out porous bones. there would seem to be no conceivable connection between pycnodysostosis and osteoporosis. the new findings about cathepsin k and pycnodysostosis have made it clear that cathepsin k is a major protease in bone resorption. given this function it may well have a role in osteoporosis. cathepsin k may in fact provide a rational basis for a new approach to the treatment of osteoporosis. this is an excellent illustration of how research on a rare disease may bring benefits to those affected by a common disease.
could there be a connection between pycnodysostosis and osteoporosis?