Campomelic dysplasia

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Campomelic dysplasia is a severe disorder that affects development of the skeleton, reproductive system, and other parts of the body. This condition is often life-threatening in the newborn period.

The term "campomelic" comes from the Greek words for "bent limb." Affected individuals are typically born with bowing of the long bones in the legs, and occasionally, bowing in the arms. Bowing can cause characteristic skin dimples to form over the curved bone, especially on the lower legs. People with campomelic dysplasia usually have short legs, dislocated hips, underdeveloped shoulder blades, 11 pairs of ribs instead of 12, bone abnormalities in the neck, and inward- and upward-turning feet (clubfeet). These skeletal abnormalities begin developing before birth and can often be seen on ultrasound. When affected individuals have features of this disorder but do not have bowed limbs, they are said to have acampomelic campomelic dysplasia.

Approximately 75 percent of affected individuals with a typical male chromosome pattern (46,XY) have normal female genitalia or genitalia that do not look clearly male or clearly female. Internal reproductive organs may not correspond with the external genitalia; the internal organs can be male (testes), female (ovaries), or a combination of the two. For example, an individual with female external genitalia may have testes or a combination of testes and ovaries.

Affected individuals have distinctive facial features, including a small chin, prominent eyes, and a flat face. They also have a large head compared to their body size. A particular group of physical features, called Pierre Robin sequence, is common in people with campomelic dysplasia. Pierre Robin sequence includes an opening in the roof of the mouth (a cleft palate), a tongue that is placed further back than normal (glossoptosis), and a small lower jaw (micrognathia). People with campomelic dysplasia are often born with weakened cartilage that forms the upper respiratory tract. This abnormality, called laryngotracheomalacia, partially blocks the airway and causes difficulty breathing. Laryngotracheomalacia contributes to the poor survival of infants with campomelic dysplasia.

Only a few people with campomelic dysplasia survive past infancy. As these individuals age, they may develop an abnormal curvature of the spine (scoliosis) and other spine abnormalities that compress the spinal cord. People with campomelic dysplasia may also have short stature and hearing loss.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Mutations in or near the SOX9 gene cause campomelic dysplasia. This gene provides instructions for making a protein that plays a critical role in the formation of many different tissues and organs during embryonic development. The SOX9 protein regulates the activity of other genes, especially those that are important for development of the skeleton and reproductive organs.

Most cases of campomelic dysplasia are caused by mutations within the SOX9 gene. These mutations prevent the production of the SOX9 protein or result in a protein with impaired function. About 5 percent of cases are caused by chromosome abnormalities that occur near the SOX9 gene; these cases tend to be milder than those caused by mutations within the SOX9 gene. The chromosome abnormalities disrupt regions of DNA that normally regulate the activity of the SOX9 gene. All of these genetic changes prevent the SOX9 protein from properly controlling the genes essential for normal development of the skeleton, reproductive system, and other parts of the body. Abnormal development of these structures causes the signs and symptoms of campomelic dysplasia.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Campomelic dysplasia is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in or near the SOX9 gene and occur in people with no history of the disorder in their family. Rarely, affected individuals inherit a chromosome abnormality from a parent who may or may not show mild signs and symptoms of campomelic dysplasia.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

The prevalence of campomelic dysplasia is uncertain; estimates range from 1 in 40,000 to 200,000 people.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

11 pairs of ribs · Very frequent (99-80%)

Presence of only 11 pairs of ribs.

Bowing of the long bones · Very frequent (99-80%)

A bending or abnormal curvature of a long bone.

Cleft palate · Very frequent (99-80%)

Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate).

Fibular hypoplasia · Very frequent (99-80%)

Underdevelopment of the fibula.

Flat face · Very frequent (99-80%)

Absence of concavity or convexity of the face when viewed in profile.

Hip dislocation · Very frequent (99-80%)

Displacement of the femur from its normal location in the hip joint.

Laryngomalacia · Very frequent (99-80%)

Laryngomalacia is a congenital abnormality of the laryngeal cartilage in which the cartilage is floppy and prolapses over the larynx during inspiration.

Macrocephaly · Very frequent (99-80%)

Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.

Other findings in the same source

From: Orphanet

Additional reported features include Micrognathia (Very frequent (99-80%)); Narrow chest (Very frequent (99-80%)); Poorly ossified cervical vertebrae (Very frequent (99-80%)); Recurrent fractures (Very frequent (99-80%)); Scoliosis (Very frequent (99-80%)); Short long bone (Very frequent (99-80%)); Short neck (Very frequent (99-80%)); Tibial bowing (Very frequent (99-80%)); Tracheobronchomalacia (Very frequent (99-80%)); Hypoplastic inferior ilia (Very frequent (99-80%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Campomelic dysplasia is Orthopaedics, with a orthopaedic specialist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• What explains the change in pain, movement or function?
• Which activities need adjustment while the diagnosis is being clarified?
• What are the roles of rehabilitation, observation and surgery in this situation?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Campomelic dysplasia. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.