Ring chromosome 20

Title

Other Names:

Chromosome 20 ring; Ring 20; R20; Chromosome 20 ring; Ring 20; R20; Ring chromosome 20 syndrome See More

Categories:

Chromosome Disorders; Congenital and Genetic Diseases; Nervous System Diseases

Summary Summary

Ring chromosome 20 is a chromosome abnormality that affects the development and function of the brain. People with ring chromosome 20 often have recurrent seizures or epilepsy. Other symptoms might include intellectual disability, behavioral difficulties, growth delay, short stature, a small head (microcephaly), and characteristic facial features. Ring chromosome 20 is caused by an abnormal chromosome known as a ring chromosome 20 or r(20). A ring chromosome is a circular structure that occurs when a chromosome breaks in two places and its broken ends fuse together. Ring chromosome 20 is usually not inherited. It almost always occurs by chance during the formation of reproductive cells (eggs or sperm) or in early embryonic development.^[1] Treatment for ring chromosome 20 is focused on management of seizures and accommodations for learning.^[2]

Last updated: 1/26/2016

Treatment Treatment

Treatment of ring chromosome 20 is typically focused on management of seizures. The seizures associated with ring chromosome 20 do not generally respond well to medications. The treatment that is successful varies from person to person. ‘Broad spectrum’ AEDs are usually tried first since they are active against different seizure types. This includes valproate, levetiracetam, lamotrigine, topiramate and zonisamide. Success has been reported in some people with a combination of valproate and lamotrigine, but so far no single therapy has worked for everyone.

Vagus nerve stimulation (VNS) has been tried and a reduction in seizures has been
reported in some cases but not in others. This involves implanting a medical device
under the skin, similar to a pacemaker that delivers a mild electrical current to the brain via the vagus nerve. The long-term effectiveness of VNS therapy is not yet known.

The ketogenic diet, which is high in fat and low in carbohydrate, has been shown to be
helpful in other types of epilepsy. However there are no published reports about whether this is successful or not in ring chromosome 20 epilepsy.^[2]

For more information on treatment of seizures in people with R20 and general information on ring chromosome 20, visit the following link from Unique, The Rare Chromosome Disorder Support Group, a non-profit organization that supports chromosomal disorders.
http://www.rarechromo.org/information/Chromosome%2020/Ring%2020%20FTNW.pdf

Last updated: 1/26/2016

Organizations Organizations

Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD. Suggest an organization to add.

Organizations Supporting this Disease

Chromosome Disorder Outreach
PO Box 724
Boca Raton, FL 33429
Telephone: 561-395-4252
E-mail: info@chromodisorder.org
Website: http://www.chromodisorder.org
Unique – Rare Chromosome Disorder Support Group
G1, The Stables
Station Road West
Surrey
RH8 9EE
United Kingdom
Telephone: +44 (0)1883 723356
E-mail: info@rarechromo.org
Website: http://www.rarechromo.org

Learn More 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.

Where to Start

Genetics Home Reference (GHR) contains information on Ring chromosome 20. This website is maintained by the National Library of Medicine.
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 20.

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.
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 20. Click on the link to view a sample search on this topic.