About cleidocranial dysplasia

What is cleidocranial dysplasia?

Cleidocranial dysplasia is a rare skeletal dysplasia characterized by short stature, distinctive facial features and narrow, sloping shoulders caused by defective or absent collarbones (clavicles). Major symptoms may include premature closing of the soft spot on the head (coronal), delayed closure of the space between the bones of the skull (fontanels), narrow and abnormally shaped pelvic and pubic bones and deformations in the chest (thoracic region). Delayed eruption of teeth, moderately short stature, a high arched palate, a wide pelvic joint, failure of the lower jaw joints to unite, and fingers that are irregular in length may also be present. Cleidocranial dysplasia is inherited as an autosomal dominant genetic trait.

What are the symptoms for cleidocranial dysplasia?

The most prominent feature of cleidocranial dysplasia is a premature closure of the two soft spots on the head (fontanels) and the fibrous joints where bones of the skull meet (sutures) causing abnormal development of the skull. Facial features typically include a prominent forehead, unusually wide face, prominent chin, small upper jaw (maxillary hypoplasia) and bulging of the skull cap. Narrow drooping shoulders caused by complete or partial absence of collarbones (clavicles) are also apparent in patients with this disorder. There may be abnormalities of the muscles in the area of the collarbones allowing for a wide range of movement of the shoulders.

Other bone abnormalities that have been found in some patients with Cleidocranial dysplasia may be: a wide pelvic joint, delayed growth of the pubic bone, a hip defect in which the thigh bone angles towards the center of the body (coxa vara), failure of the lower jaw bones to unite, a defect of the hip that causes the thigh bone to angle out to the side of the body (coxa valga), curvature of the spine (scoliosis), a small shoulder blade, and/or curvature of the upper legs so that the knees appear unusually close together (genu valgum).

Dental abnormalities may include: a delay in tooth eruption, incomplete development or absence of teeth, underdeveloped enamel and/or extra teeth. Cysts may form around the unerupted or displaced teeth in some cases. A high-arch palate or a condition in which there is a hole in the roof of the mouth (cleft palate) may be present.

Individuals with cleidocranial dysplasia have an increased risk for recurrent ear and sinus infections, upper respiratory complications and hearing loss.

What are the causes for cleidocranial dysplasia?

Cleidocranial dysplasia is a rare disorder that is usually inherited as an autosomal dominant genetic trait. Affected individuals can show a wide range of symptoms (variable expression). Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.

The gene for cleidocranial dysplasia has been mapped to chromosome 6p21 and has been designated CBFA1.

Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated “p” and a long arm designated “q”. Chromosomes are further sub-divided into many bands that are numbered. For example, “chromosome 6p21” refers to band 21 on the short arm of chromosome 6. The numbered bands specify the location of the thousands of genes that are present on each chromosome.

What are the treatments for cleidocranial dysplasia?

Head gear may be worn to protect the skull bones until they close. Appropriate dental care should be provided. When cleft palate is present surgery may be performed to close or block the opening. Hearing evaluations should be performed at birth and during early childhood.

Affected individuals have an increased risk for sleep apnea, sinus infections and ear infections due to delayed craniofacial development and should be monitored for these problems. Speech and language may also need to be assessed by a speech pathologist.

Genetic counseling may be of benefit for patients and their families. Other treatment is symptomatic and supportive.

The National Craniofacial Association lists several medical centers throughout the United States and Canada that specialize in treating this disorder. Contact information for this organization can be found in the Resources section of this report.

What are the risk factors for cleidocranial dysplasia?

A rare condition known as cleidocranial dysplasia is often inherited as an autosomal dominant genetic characteristic. People who are affected can display a variety of symptoms (variable expression).

1. When just one copy of a defective gene is required for the disease to manifest, dominant genetic diseases result.
2. The faulty gene may be brought on by a new mutation (gene alteration) in the sick person, or it may be inherited from either parent. Regardless of the sex of the offspring, there is a 50% chance that the faulty gene will be passed from the affected parent to their offspring throughout each pregnancy.
3. The chromosome 6p21 region has been identified as the location of the CBFA1 gene, which causes cleidocranial dysplasia.
4. Human cells contain chromosomes, which house the genetic material that makes each person unique. 46 chromosomes typically make up human body cells. The sex chromosomes are referred to as X and Y, and human chromosomal pairs are numbered from 1 to 22. Females have two X chromosomes, while males have one X and one Y chromosome.
5. The short arm of each chromosome is denoted "p," and the long arm is designated "q." Chromosomes are further separated into numerous numbered bands. Band 21 on the short arm of chromosome 6 is referred to as "chromosome 6p21," for instance. Each chromosome contains hundreds of genes, and the numbered bands identify their locations.

Symptoms
Premature closing of the soft spot on the head
Conditions
Abnormally shaped pelvic and pubic bones
Drugs
NA

Is there a cure/medications for cleidocranial dysplasia?

A rare skeletal abnormality known as cleidocranial dysplasia is characterized by small stature, unusual facial characteristics, and thin, sloping shoulders that are brought on by damaged or missing collarbones (clavicles). The soft spot on the head (coronal), the space between the bones of the skull (fontanels), the thin and irregularly shaped pelvic and pubic bones, and chest deformations are all major symptoms that might occur (thoracic region).

1. The skull bones can be protected with headgear until they close. Dental care should be administered as necessary. Surgery may be used to close or block the opening in cases with cleft palate. Birth and early childhood should also include hearing examinations.

2. Due to delayed craniofacial development, affected persons are more susceptible to sleep apnea, sinus infections, and ear infections and should be watched for these issues. A speech pathologist may also need to evaluate the patient's language and speech.

3. Patients and their families may benefit from genetic counseling. Other forms of treatment are supportive and symptomatic.

4. Numerous medical facilities around the United States and Canada that specialize in treating this condition are listed by the National Craniofacial Association. The Resources section of this report includes contact information for this organization.

Symptoms
Premature closing of the soft spot on the head
Conditions
Abnormally shaped pelvic and pubic bones
Drugs
NA

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