National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Ring chromosome 18


Other Names:
Chromosome 18 ring; Ring 18; R18
Categories:
Ring chromosome 18 is a rare chromosome abnormality in which the ends (arms) of chromosome 18 join together to form a ring shape.  When a ring chromosome forms, genetic material can be lost from either arm or both arms, causing various signs and symptoms. While most people with ring chromosome 18 have the ring chromosome in all of their body cells, some people also have some body cells with normal chromosomes (this is called mosaicism). People with ring chromosome 18 mosaicism may have milder symptoms.[1]

Depending on the amount of genetic material lost and which genes are involved, signs and symptoms that may be present in a person with ring chromosome 18 include ear and hearing abnormalities, abnormally-developed feet or hands, genital abnormalities in males, an increased risk to develop juvenile rheumatoid arthritis, holoprosencephaly, developmental delays, learning difficulties, short stature, and/or various birth defects.[1]

Ring chromosome 18 usually occurs sporadically (by chance) during the formation of egg or sperm cells or shortly after the egg and sperm join together. Occasionally, it is inherited from a parent (typically the mother).[1] A chromosome test of the parents can help determine whether it was inherited and whether future children have an increased chance to have a chromosome abnormality. Treatment for ring chromosome 18 depends on the signs and symptoms present in each person.
Last updated: 6/21/2018

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Ring chromosome 18. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Ring chromosome 18:
    Chromosome 18 Registry & Research Society
     

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

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.

Where to Start

  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
  • Unique is a source of information and support to families and individuals affected by rare chromosome disorders. Click on the link to view information about ring chromosome 18.

In-Depth Information

  • The Chromosome 18 Clinical Research Center provides clinical management guidelines for people with different disorders involving chromosome 18, including Ring chromosome 18.
  • 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.
  • 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 Ring chromosome 18. Click on the link to view a sample search on this topic.

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  1. Ring 18. Unique. 2005; https://www.rarechromo.org/media/information/Chromosome%2018/Ring%2018%20FTNW.pdf.