The mechanism thought to cause HCS is an abnormality in osteoblast and osteoid function. These are major components of bone development, and the low function of each leads to the weak bones that characterize HCS.
Hajdu–Cheney syndrome
Cleidocranial dysostosis
MEDNIK syndrome
ATR-16 syndrome
Aarskog–Scott syndrome
Treacher Collins syndrome
GRACILE syndrome
Heimler syndrome