What is Cleidocranial Dysplasia

Cleidocranial dysplasia is a rare genetic condition primarily characterized by the underdevelopment or absence of collarbones (clavicles) and delayed closure of the spaces between the skull bones (fontanelles). While it affects skeletal development, most individuals with cleidocranial dysplasia lead healthy lives with normal intelligence, though they may require specialized dental and orthopedic care.

What are the primary physical characteristics of cleidocranial dysplasia?

The hallmark of cleidocranial dysplasia is the skeletal manifestation. Because the clavicles are often absent or hypoplastic, individuals can frequently bring their shoulders together in front of the chest. The condition also affects the teeth and facial structure, often resulting in delayed loss of baby teeth, the presence of supernumerary (extra) teeth, and a prominent forehead. Other common features include:

• Delayed closure of the skull sutures and fontanelles.


• Short stature compared to family members.


• Narrow, high-arched palate and potential cleft palate.


• Delayed eruption of permanent teeth.


• Increased susceptibility to ear infections and sinus issues.

What causes cleidocranial dysplasia?

Cleidocranial dysplasia is typically caused by a mutation in the RUNX2 gene, which provides instructions for making a protein essential for bone and cartilage development. This gene is a master regulator of osteoblast differentiation, meaning it tells cells how to become bone. In about 60% to 70% of cases, the condition is inherited in an autosomal dominant pattern, meaning only one copy of the altered gene is needed to cause the disorder. In other cases, it occurs as a "de novo" mutation in an individual with no family history.

How common is this condition?

Cleidocranial dysplasia is a rare disorder with an estimated prevalence of approximately 1 in 1,000,000 individuals worldwide. It affects males and females equally, and there is no known predilection for any specific ethnic or geographic group. At DiseaseMaps.org, 89 people with cleidocranial dysplasia have already joined our community to share their lived experiences and clinical insights.

Next steps

• Consult with a clinical geneticist to confirm the diagnosis through RUNX2 genetic testing.


• Schedule an evaluation with a pediatric dentist or orthodontist, as dental management is a cornerstone of care for cleidocranial dysplasia.


• Connect with the DiseaseMaps.org community to engage with other families and access peer-shared resources.


• Discuss orthopedic monitoring with a specialist if you experience chronic joint or spinal issues.

Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment.

References

• National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).


• Orphanet: The portal for rare diseases and orphan drugs.


• OMIM (Online Mendelian Inheritance in Man): Entry #119600.


• Cleidocranial Dysplasia Foundation (CCD Smiles).