Cleidocranial Dysostosis

What is cleidocranial dysostosis (aka cleidocranial dysplasia)?

Cleidocranial dysostosis is a skeletal condition that affects the development of bones and teeth. It is very rare, occurring in approximately 1 in 1 million people, but is likely underdiagnosed due to individuals who have mild symptoms. It affects males and females equally.

What are the symptoms of cleidocranial dysostosis?

Underdeveloped or absent collarbones
Narrow and sloping shoulders; ability to touch the shoulders together at the front of the body
Dental abnormalities, like delayed loss of baby teeth, delayed growth of adult teeth, misaligned teeth, extra teeth, cysts, and/or unusually shaped teeth
Short stature
Facial features: wide, short skull; wide-set eyes; small upper jaw; flat nose
Premature closing of the soft spot of the head
Delayed closing of the spaces between the skull bones
Low bone density
Hearing loss
Osteoporosis
Abnormalities in hand bones, like short fingers and broad thumbs
Ongoing sinus and ear infections
Flat feet and bowed legs
Scoliosis
Mild motor skill development, like crawling and walking

What causes cleidocranial dysostosis?

Human traits are inherited from a person’s father and mother; each one contributes a copy of a gene, which interacts with the other copy. When a gene mutates, it can lead to disease. This condition is caused by a mutation in a gene called the RUNX2 gene, which holds instructions for the body on how to make a protein that helps in the development of bone. When there’s a shortage of that normal protein, the normal development of bone and cartilage is affected. This condition is inherited in an autosomal dominant pattern, which means that only one parent needs to pass down a copy of the gene for the condition to occur. In some rare cases, people with this condition do not have a mutation in the RUNX2 gene, but the cause for those cases is currently unknown.