cleidocranial dysplasia

Cleidocranial dysplasia is an inherited congenital disability which affects the development of the bones and teeth. Typically, it is caused by the mutation of genes that are involved in bone formation. Often, people with cleidocranial dysplasia have characteristic features such as the prominent forehead, wide-set eyes, flat nose, and dental anomalies. Additionally, they also exhibit low IQ levels.

One of the typical features of cleidocranial dysplasia is poorly developed collar bones and skulls. Moreover, it can also lead to stunted growth. Dental abnormalities may lead to the formation of the small maxilla, cysts in the gums, abnormally shaped teeth, delayed tooth eruptions, and malocclusions.

Diagnosis of cleidocranial dysplasia depends on a series of gene testing and x-ray studies. The presence of a defective RUNX2 gene confirms the diagnosis of cleidocranial dysplasia. Treatment usually includes supportive measures to protect the skull. Surgical intervention may be required to treat bone abnormalities. Dental care is crucial to maintain proper oral hygiene. Today’s article will highlight the original features of cleidocranial dysplasia. Furthermore, we will discuss the causes and treatment of this congenital disability.

What is cleidocranial dysplasia?

Cleidocranial dysplasia, also known as cleidocranial dysostosis, is a congenital disability that mainly affects the growth and development of the bones and the teeth. Typically, people with cleidocranial dysplasia have poorly developed collar bones and skulls. (1)

The prevalence of cleidocranial dysplasia is about one per million people. It occurs equally in both males and females. Often, people with cleidocranial dysplasia have decreased life expectancy.

What causes cleidocranial dysplasia?

Mutations in the RUNX2 gene typically cause cleidocranial dysplasia. This gene is responsible for the development and maintenance of the bones, cartilage, and teeth.

Researchers say that the gene mutation eliminates the activity of the protein that is used for bone development in each cell. As a result, it decreases the amount of functional RUNX2 in the body. The shortage of protein interferes with the normal growth and development of the bone, teeth, and cartilage. (2) In rare cases of cleidocranial dysplasia, deletion of the RUNX2 gene may lead to developmental delays

What are the signs and symptoms of cleidocranial dysplasia?

As the name suggests, ‘cleido’ means collar bone, ‘cranial’ means skull, and ‘dysplasia’ means deformity. Some of the clinical signs and symptoms of cleidocranial dysplasia are listed below –

Bone disorders

  • Usually, painless swelling in the area of the clavicles (collar bones) may be seen as early as 2-3 years of age. In 10% of the cases, the part of the clavicle may be missing. This allows hypermobility of the shoulders. (3)
  • Partial collar bones often cause nerve damage
  • Short stature due to underdeveloped bones and joints
  • Delayed ossification of bones
  • Short middle fifth phalanges

Skull deformity

  • Failure of the fontanelles to close leaving a soft spot on the surface of the skull
  • Bulging of the forehead
  • Open skull sutures
  • Hypertelorism
  • Vertebral abnormalities leading to spina bifida and scoliosis

Dental abnormalities

  • Prognathic mandible
  • Hypoplastic maxilla
  • Growth of supernumerary teeth in the permanent dentition cause overcrowding of the teeth in the jaw (4)
  • Displaced adjacent teeth
  • Defective cementum formation
  • Delayed or failure of permanent teeth eruption
  • Formation of cysts and abscess in the gums

Many individuals have tapered fingers, broad thumb, flat feet, and knock knees. In some cases, people with cleidocranial dysplasia may show decreased bone density. Furthermore, they may develop osteoporosis.

Pregnant women with cleidocranial dysplasia often have a narrow pelvis, which may obstruct the passage during delivery. Ear and sinus infections are some of the common complications of cleidocranial dysplasia.

How is cleidocranial dysplasia diagnosed?

Typically, the healthcare professional may take a complete patient history to rule out the presence of cleidocranial dysplasia in the family. Physical examinations are performed to check the hypermobility of the shoulders and soft spots in the skull.

Diagnosis mainly includes radiographic studies to check for dysplastic features of the skull and collar bones. A series of gene tests are performed to identify the defective RUNX2 gene responsible for the growth and development of the bones, teeth, and cartilage. (5)

What is the treatment for cleidocranial dysplasia?

Treatment depends upon the severity of the symptoms.

  • Usually, surgical corrections may be performed around the age of five years. This is done to prevent any worsening of the bone deformity.
  • Pregnant mothers with this disability may have to undergo caesarian delivery.
  • Craniofacial surgeries are performed to correct skull defects (6)
  • Dental treatments such as tooth restoration, replacement of missing teeth, and fluoride treatments are performed to maintain oral health and hygiene.

Take away message

Cleidocranial dysplasia is a congenital disability that primarily affects the growth and development of the bones and the teeth. Typically, this condition is inherited and caused by gene mutations that eliminate the activity of the protein used to build the bones and teeth.

Clinical features of cleidocranial dysplasia include – hypermobility of the shoulders, open fontanelles, short stature, flat nose, narrow pelvis, missing collar bone, hypertelorism, and bulging of the forehead. Additionally, cleidocranial dysplasia also causes dental abnormalities. Some of them include – small maxilla and facial bones, abnormally shaped teeth, supernumerary teeth, failure of permanent teeth eruption, and increased risk of cyst formation in the gums.

Diagnosis of cleidocranial dysplasia mainly depends on the radiographic studies and gene testing. Treatment may be offered according to the type of defect present. It is essential to understand the severity of this condition and seek immediate care to prevent the worsening of the symptoms.