Campomelic dysplasia

What is campomelic dysplasia?

Campomelic dysplasia is a severe disorder that affects the development of the skeleton and reproductive system. 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 they are occasionally born with 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 also usually have short legs, dislocated hips, underdeveloped shoulder blades, 11 pairs of ribs instead of 12, bone abnormalities in the neck, and feet that are abnormally rotated (club feet). When affected individuals have features of this disorder but do not have bowed limbs, they are said to have acampomelic campomelic dysplasia.

Many people with campomelic dysplasia have external genitalia that do not look clearly male or clearly female (ambiguous genitalia). Approximately 75 percent of affected individuals with a typical male chromosome pattern (46,XY) have ambiguous genitalia or normal female genitalia. Internal reproductive organs may not correspond with the external genitalia; they can be male (testes), female (ovaries), or a combination of the two.

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.

How common is campomelic dysplasia?

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

What genes are related to campomelic dysplasia?

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 around the SOX9 gene. These 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.

Read more about the SOX9 gene.

How do people inherit campomelic dysplasia?

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.

Where can I find information about treatment for campomelic dysplasia?

These resources address the management of campomelic dysplasia and may include treatment providers.

• Cedars-Sinai Medical Center: International Skeletal Dysplasia Registry
• European Skeletal Dysplasia Network
• Gene Review: Campomelic Dysplasia
• MedlinePlus Encyclopedia: Ambiguous Genitalia
• MedlinePlus Encyclopedia: Pierre-Robin Syndrome

You might also find information on treatment of campomelic dysplasia in Educational resources and Patient support.

Where can I find additional information about campomelic dysplasia?

You may find the following resources about campomelic dysplasia helpful. These materials are written for the general public.

• MedlinePlus - Health information (4 links)
• Educational resources - Information pages (4 links)
• Patient support - For patients and families (6 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

• Gene Reviews - Clinical summary
• Gene Tests - DNA tests ordered by healthcare professionals
• PubMed - Recent literature
• Online Books - Medical and science texts
• Scriver's Online Metabolic and Molecular Bases of Inherited Disease (OMMBID): Campomelic Dysplasia/Autosomal Sex Reversal/SOX9
• OMIM - Genetic disorder catalog

What other names do people use for campomelic dysplasia?

• Campomelic dwarfism
• Campomelic syndrome
• Camptomelic dysplasia

See How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about campomelic dysplasia?

• See How can I find a genetics professional in my area? in the Handbook.
• Ask the Genetic and Rare Diseases Information Center.
• Submit your question to Ask the Geneticist.

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

• What does it mean if a disorder seems to run in my family?
• What are the different ways in which a genetic condition can be inherited?
• If a genetic disorder runs in my family, what are the chances that my children will have the condition?
• Why are some genetic conditions more common in particular ethnic groups?

These links provide additional genetics resources that may be useful.

• Genetics and health
• Resources for Patients and Families
• Resources for Health Professionals

What glossary definitions help with understanding campomelic dysplasia?

autosomal ; autosomal dominant ; cartilage ; cell ; chromosome ; cleft palate ; club foot ; DNA ; dwarfism ; dysplasia ; embryonic ; gene ; genitalia ; micrognathia ; mutation ; new mutation ; ovary ; palate ; prevalence ; protein ; respiratory ; scoliosis ; short stature ; sign ; stature ; symptom ; syndrome ; testes ; tissue

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References

These sources were used to develop the Genetics Home Reference condition summary on campomelic dysplasia.

• Beaulieu Bergeron M, Lemyre E, Rypens F, Scherer G, Lemieux N, Fournet JC. Diagnosis of true hermaphroditism in a fetus with acampomelic campomelic dysplasia. Prenat Diagn. 2009 Feb 27; [Epub ahead of print] No abstract available. PubMed citation
• Bien-Willner GA, Stankiewicz P, Lupski JR. SOX9cre1, a cis-acting regulatory element located 1.1 Mb upstream of SOX9, mediates its enhancement through the SHH pathway. Hum Mol Genet. 2007 May 15;16(10):1143-56. Epub 2007 Apr 4. PubMed citation
• Gene Review: Campomelic Dysplasia
• Hill-Harfe KL, Kaplan L, Stalker HJ, Zori RT, Pop R, Scherer G, Wallace MR. Fine mapping of chromosome 17 translocation breakpoints > or = 900 Kb upstream of SOX9 in acampomelic campomelic dysplasia and a mild, familial skeletal dysplasia. Am J Hum Genet. 2005 Apr;76(4):663-71. PubMed citation
• Kobayashi A, Chang H, Chaboissier MC, Schedl A, Behringer RR. Sox9 in testis determination. Ann N Y Acad Sci. 2005 Dec;1061:9-17. Review. PubMed citation
• Leipoldt M, Erdel M, Bien-Willner GA, Smyk M, Theurl M, Yatsenko SA, Lupski JR, Lane AH, Shanske AL, Stankiewicz P, Scherer G. Two novel translocation breakpoints upstream of SOX9 define borders of the proximal and distal breakpoint cluster region in campomelic dysplasia. Clin Genet. 2007 Jan;71(1):67-75. PubMed citation
• Mansour S, Offiah AC, McDowall S, Sim P, Tolmie J, Hall C. The phenotype of survivors of campomelic dysplasia. J Med Genet. 2002 Aug;39(8):597-602. No abstract available. PubMed citation
• Pop R, Zaragoza MV, Gaudette M, Dohrmann U, Scherer G. A homozygous nonsense mutation in SOX9 in the dominant disorder campomelic dysplasia: a case of mitotic gene conversion. Hum Genet. 2005 Jun;117(1):43-53. Epub 2005 Apr 2. PubMed citation
• Scriver's Online Metabolic and Molecular Bases of Inherited Disease (OMMBID): Campomelic Dysplasia/Autosomal Sex Reversal/SOX9
• Smyk M, Obersztyn E, Nowakowska B, Bocian E, Cheung SW, Mazurczak T, Stankiewicz P. Recurrent SOX9 deletion campomelic dysplasia due to somatic mosaicism in the father. Am J Med Genet A. 2007 Apr 15;143A(8):866-70. PubMed citation
• Velagaleti GV, Bien-Willner GA, Northup JK, Lockhart LH, Hawkins JC, Jalal SM, Withers M, Lupski JR, Stankiewicz P. Position effects due to chromosome breakpoints that map approximately 900 Kb upstream and approximately 1.3 Mb downstream of SOX9 in two patients with campomelic dysplasia. Am J Hum Genet. 2005 Apr;76(4):652-62. Epub 2005 Feb 22. PubMed citation