Rare Pediatrics News

Disease Profile


Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

<1 / 1 000 000

US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)



Congenital and Genetic Diseases; Musculoskeletal Diseases


Metachondromatosis (MC) is a rare bone disorder characterized by the presence of both multiple enchondromas and osteochondroma-like lesions. The first signs occur during the first decade of life. Osteochondromas most commonly occur in the hands and feet (predominantly in digits and toes), and enchondromas involve the iliac crests and metaphyses of long bones. The lesions typically spontaneously decrease in size or regress. Nerve paralysis or vascular complications may occur in some cases. The condition has been linked to mutations in the PTPN11 gene in several families and is inherited in an autosomal dominant manner. Treatment may include surgery to remove osteochondromas in severe cases.[1][8171]


Metachondromatosis (MC) is characterized by the presence of both multiple enchondromas and osteochondromas. The features of the condition generally become apparent in the first decade of life.[1]

Enchondromas are benign (noncancerous) tumors that appear on the inside of the bone.[2] Those that are associated MC typically involve the iliac crests (part of the pelvis) and metaphyses of long bones, particularly the proximal femur (portion of the thigh bone closer to the trunk).[1][3] These tumors are usually painless, but when they appear in the hands or feet, or in multiple lesions (as is typical in MC), they can deform the bone.[2]

Osteochondromas are also benign tumors. These form on the surface of the bone near the growth plates (areas of developing cartilage tissue near the ends of long bones in children) and are made up of both bone and cartilage. Osteochondromas may grow as the affected child grows, and stop growing when the child reaches skeletal maturity.[4] They have a tendency to regress or disappear after the first or second decade of life.[3] Those that are associated with MC most frequently occur in the small bones of the hands and feet, predominantly in digits and toes.[1][3] The characteristic location and orientation of these in individuals with MC (as well as lack of bone shortening and short stature) are what generally differentiate MC from hereditary multiple osteochondromas (HMO), a disorder with overlapping features.[3] The osteochondromas of MC point toward the joint to which they are adjacent (whereas those of HMO point away).[3] Osteochondromas often cause painless bumps, but pain or other discomfort may occur if the tumors put pressure on soft tissues, nerves, or blood vessels.[4]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Abnormality of epiphysis morphology
Abnormal shape of end part of bone
Abnormality of the metaphysis
Abnormality of the wide portion of a long bone
Avascular necrosis
Death of bone due to decreased blood supply
Bone pain
Cranial nerve paralysis
Formation of new noncancerous bone on top of existing bone
Multiple enchondromatosis
Percent of people who have these symptoms is not available through HPO
Abnormal joint morphology
Abnormal shape of joints
Abnormality of the joints
Anomaly of the joints

[ more ]

Autosomal dominant inheritance
Bowing of the long bones
Bowed long bones
Bowing of long bones

[ more ]

Multiple digital exostoses


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      In-Depth Information

      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
      • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Metachondromatosis. Click on the link to view a sample search on this topic.

        Selected Full-Text Journal Articles


          1. Judith Bovee and Christianne Reijnders. Metachondromatosis. Orphanet. May 2011; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=2499. Accessed 10/8/2012.
          2. Enchondroma. American Academy of Orthopaedic Surgeons. June 2010; https://orthoinfo.aaos.org/topic.cfm?topic=A00085. Accessed 10/8/2012.
          3. Vining NC et al. EXT2-positive multiple hereditary osteochondromas with some features suggestive of metachondromatosis. Skeletal Radiol. May 2012; 41(5):607-610.
          4. Osteochondroma. American Academy of Orthopaedic Surgeons. May 2012; https://orthoinfo.aaos.org/topic.cfm?topic=A00079. Accessed 10/8/2012.

          Rare Pediatrics News