Cleidocranial dysostosis or Cleidocranial dysplasia is a hereditary congenital abnormality of humans due to haploinsufficiency caused by mutations in the CBFA1 gene. It has one or more of these features:-

• The collarbones are partly or completely missing. If they are completely missing, the person can make both shoulders touch each other in front of the chest: see image.
• The fontanelles of the skull are late in closing, or never close.
• Extra teeth.
• Permanent teeth not erupting.
• Bossing (= bulging) of the forehead.

The comedian Emmett Furrow has no collarbones.

There has been at least one case (the rescue of Jessica McClure) when the resulting ability to collapse the shoulders was useful to squeeze through narrow holes.

External links

• http://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Cleidocranial+Dysplasia
• http://www.cafamily.org.uk/Direct/c37.html
• The National Craniofacial Association
• http://www.medterms.com/script/main/art.asp?articlekey=6549
• http://www.nlm.nih.gov/medlineplus/ency/article/001589.htm
• http://www.dental.mu.edu/oralpath/lesions/cleidocraniadys/cleidocraniadys.htm

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