• What is cleidocranial dysplasia?
• How does a person acquire CCD?
• What is the molecular genetic basis for CCD?
• Cleidocranial dysplasia (CCD) At A Glance

What is cleidocranial dysplasia?

Cleidocranial dysplasia (CCD) is a genetic (inherited) disorder of bone development which is characterized by:

1. Absent or incompletely formed collar bones (the "cleido-" part refers to the clavicles, the collar bones). A person with this condition can bring his/her shoulders together or nearly so; and
2. Typical cranial and facial abnormalities with square skull, late closure of the sutures of the skull, late closure of the fontanels (the soft spots), low nasal bridge, delayed eruption of the teeth, abnormal permanent teeth, etc.

How does a person acquire CCD?

The disorder is transmitted genetically in an autosomal dominant manner. This means that one parent with the condition has a 50:50 chance of passing CCD to each of their children. Boys and girls are equally affected.

What is the molecular genetic basis for CCD?

The gene for CCD has been found on chromosome 6 (specifically, in band p21) and been identified. It is the gene for the transcription factor CBFA1 (core-binding factor alpha subunit 1). Mutations of CBFA1 cause cleidocranial dysplasia.

Cleidocranial dysplasia (CCD) At A Glance

• Cleidocranial dysplasia (CCD) is a bone disorder which is present from birth.
• The collar bones are underdeveloped or absent in CCD.
• A person with CCD can bring his/her shoulders together in front.
• Characteristic CCD cranial and facial abnormalities include a square skull.
• CCD is inherited as an autosomal dominant trait from generation to generation and affects boys and girls equally.
• The gene for CCD has been identified on chromosome 6 and is called CBFA1.