Cleidocranial dysplasia is a rare genetic condition that affects the development of bones and teeth. It can cause features such as a flat, broad nose, short stature, and extra teeth or delayed tooth eruption.
The condition, also known as cleidocranial dysostosis, is most commonly associated with changes in the RUNX2 gene, also known as CBFA1, and may also involve the CBFB gene. In some cases, however, the exact cause is unknown.
Treatment for cleidocranial dysplasia is planned according to each person's individual needs. It may include dental treatment, speech therapy, medications and supplements, and nutritional care.
Typical characteristics
The characteristics and symptoms of cleidocranial dysplasia may include:
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Delayed closure of a baby's fontanelle;
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Prominent chin and forehead;
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Flat, very broad nose;
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A very narrow roof of the mouth that is higher than normal;
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Short or absent collarbones;
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Narrow, highly flexible shoulders;
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Short stature;
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Extra teeth or delayed tooth eruption.
People with cleidocranial dysplasia may also have hypertelorism, which means the eyes are spaced farther apart than normal.
The condition can also affect the spine, causing scoliosis and short stature.
Changes in the facial bones can also alter the nasal cavities, which may make children more prone to sinus infections.
Confirming a diagnosis
Cleidocranial dysplasia is usually diagnosed by a pediatrician after identifying the characteristic features of the condition.
However, in many cases, the first signs may be noticed during a dental appointment, such as extra teeth or delayed tooth eruption.
To confirm the diagnosis, the doctor may order imaging tests, such as X-rays of the skull or chest or a panoramic dental X-ray.
Genetic testing may also be performed to identify a disease-causing change in the RUNX2 gene, also known as CBFA1.
In some cases, cleidocranial dysplasia may be identified as early as the 14th week of pregnancy through ultrasound or genetic testing.
Possible causes
The causes of cleidocranial dysplasia include:
1. RUNX2 or CBFA1 gene alteration
An alteration in the RUNX2 gene, also known as CBFA1, is the most common cause of cleidocranial dysplasia. It occurs when one copy of the gene does not work properly, preventing the body from producing enough protein for normal bone and tooth development.
This genetic alteration can be inherited when it is passed from a parent to a child, or it can occur spontaneously during the formation of reproductive cells or early embryonic development.
In either case, a RUNX2 alteration causes the typical features of cleidocranial dysplasia by affecting bone and tooth development from the earliest stages of life.
2. CBFB gene mutation
A condition similar to cleidocranial dysplasia can be caused by a mutation in the CBFB gene because this gene plays an important role in the proper function of RUNX2.
The CBFB protein binds to RUNX2 and helps stabilize its interaction with DNA, allowing genes involved in normal bone and tooth development to be activated.
When CBFB is altered, RUNX2 may not work efficiently even when the RUNX2 gene itself is normal. This can interfere with bone and tooth development and lead to a form of cleidocranial dysplasia that resembles the classic form but may have some different features, such as generally normal height and mild to moderate developmental delay.
3. Unknown cause
In some cases of cleidocranial dysplasia, the characteristic features are present even though the responsible genetic alteration cannot be identified.
This suggests that other genes or mechanisms that have not yet been identified may also be involved in abnormal bone and tooth development.
Treatment options
Some people with cleidocranial dysplasia may not need specific treatment. However, specialists may recommend different treatments and supportive measures based on each person's symptoms and needs.
1. Dental treatments
Dental treatment for cleidocranial dysplasia aims to preserve as many natural teeth as possible, improve chewing, and improve appearance.
Treatment is usually performed in several stages and may include removing baby teeth and extra teeth, followed by exposing teeth that have not yet erupted and using orthodontic braces.
In some cases, surgery may be needed to correct problems with the bite or jaw development. This type of surgery is generally recommended after growth is complete.
2. Speech therapy
Speech therapy is used to improve communication when dental, jaw, or hearing abnormalities affect pronunciation.
The goal is to support clear speech and appropriate language development throughout treatment.
Treatment may involve ongoing assessments and exercises that focus on speech sounds, helping the person adapt to changes in the mouth and to any hearing difficulties.
3. Medications and supplements
Medications and supplements recommended by a doctor may include:
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Calcium and vitamin D supplements when there is a deficiency in these nutrients or reduced bone mineral density;
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Medications used to treat osteoporosis or osteopenia, such as bisphosphonates, in selected cases involving bone fragility or recurrent fractures;
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Growth hormone, only when growth hormone deficiency or an abnormality involving the IGF-1 axis has been confirmed.
These treatments are recommended according to each person's individual condition and are not routinely prescribed.
Medications and supplements may help improve bone mineralization, reduce the risk of fractures, and support growth within the limitations of the genetic condition.
4. Nutritional treatment
Nutritional treatment is part of ongoing care and aims to support a child's growth and bone health.
It focuses on monitoring height, identifying and addressing possible nutritional problems, and ensuring adequate calcium and vitamin D intake to help strengthen bones and reduce the risk of fractures.
Monitoring begins early in life and continues throughout the growth period to support the best possible physical development.
5. Hearing and airway protection
An otolaryngologist may monitor hearing, maintain healthy airways, and manage infections.
Treatment may include managing ear infections and sinus infections and placing tympanostomy tubes in cases of recurrent middle ear infections to help prevent hearing loss.
Treatment for airway obstruction, including sleep apnea, may also be recommended by the doctor and may require surgery.