Cleidocranial dysostosis

Cleidocranial dysostosis or Cleidocranial dysplasia is a hereditary congenital abnormality of humans due to haploinsufficiency caused by mutations in the CBFA1 gene.

Presentation
It has one or more of these features:
 * The collarbones are partly or completely missing. If they are completely missing, the shoulders can touch each other in front of the chest.
 * The fontanelles of the skull are late in closing, or never close.
 * Extra teeth
 * Permanent teeth not erupting.
 * Bossing (= bulging) of the forehead.

Notable cases
Although he has not said he has the condition, the comedian Emmett Furrow has no collarbones.