Juvenile Huntington disease

What causes juvenile Huntington disease (HD)?

Juvenile HD, like adult-onset HD, is caused by mutations in the HTT gene. This gene gives the body instructions for making a protein called huntingtin, which is thought to be important for nerve cells (neurons) in the brain. When the huntingtin protein does not function properly, it is thought to cause the death of neurons in certain areas of the brain, causing the symptoms of juvenile HD.

The mutation in the HTT gene that causes HD involves a DNA segment known as a CAG trinucleotide repeat. This segment is made up of a series of three DNA building blocks (cytosine, adenine, and guanine) that normally appear multiple times in a row. In people without HD, the CAG segment is repeated 10 to 35 times within the gene. In people with juvenile HD, the CAG segment is repeated more than 60 times.

Last updated on 05-01-20

How is juvenile Huntington disease (HD) diagnosed?

Juvenile HD is diagnosed based on evaluation of symptoms, the family history, and genetic test results - ideally by a pediatric neurologist. Neurological symptoms may need to be evaluated over several doctor appointments. No one symptom or group of symptoms is necessary for the diagnosis, but most children with juvenile HD have several symptoms by the time they are evaluated. Parents of children being evaluated may fear that their child's symptoms are due to juvenile HD, but it is important to remember that children can have developmental or neurological disorders that are unrelated to HD.

In most cases, a child or teenager with juvenile HD has a parent with HD. However in some cases, the family history "appears" negative. This may be the case if a parent has died before symptoms began, if a parent has not yet been diagnosed, or if the father is not the biological father (non-paternity). If the family history is truly negative, other causes for the child's symptoms may be explored. If the family history is positive or the physician suspects the disease is present, genetic testing can be ordered to confirm or rule out the diagnosis of HD.

Last updated on 05-01-20

How is juvenile Huntington disease (HD) inherited?

Juvenile HD is inherited in an autosomal dominant manner, which means that one copy of the altered gene in each cell is sufficient to cause the disorder. An affected person usually inherits the altered gene from one affected parent. As the altered HTT gene is passed from one generation to the next, the size of the CAG trinucleotide repeat responsible for HD often increases in size. A larger number of repeats is usually associated with an earlier onset of signs and symptoms. This phenomenon is known as anticipation. Most often, children with juvenile HD inherit the expanded CAG trinucleotide repeat from their father, although on occasion they inherit it from their mother.

Last updated on 05-01-20

How might Juvenile Huntington disease (HD) be treated?

Currently there is no cure for juvenile HD, and there is no way to slow or stop the progression of the disease. Treatment therefore aims to relieve symptoms and increase quality of life. A number of medications are available to help control or ease muscle stiffness, dystonia, and chorea. Physical and occupational therapy may also be helpful for temporarily easing these symptoms, developing strategies for moving around, and preventing falls. Medications are also available to help with seizures, as well as behavioral or psychiatric problems such as attention deficit or depression. Unfortunately, there are no medications known to improve thinking ability (cognitive function) in people with HD.

The family of a child with juvenile HD should meet with school representatives to develop an Individual Education Plan (IEP), which should be reviewed frequently as the disease progresses.

Last updated on 05-01-20

Clinical Research Resources

Huntington Study Group

The Huntington Study Group (HSG) is a non-profit group of clinical investigators from medical centers in the United States, Canada, Europe, Australia, New Zealand and South America, experienced in the care of Huntington patients and dedicated to clinical research of Huntington disease (HD). Click on the link to learn more about research trials that are currently underway.

Last updated on 04-27-20

In-Depth Information

European Huntington's Disease Network

The European Huntington's Disease Network offers diverse resources, including treatment guidelines, support for patients and their families, finding specialists, and research opportunities for investigators.

Last updated on 04-27-20

Patient Registry

Hereditary Disease Foundation

The National Research Roster for Huntington Disease Patients and Families (hdRoster) was established in 1979 at Indiana University. Funded by the National Institute of Neurological Disorders and Stroke, a branch of the National Institutes of Health, the Roster computerizes the names of families, including information about the history of HD in the family (family trees) and other related data. This information identifies HD patients and families who are interested in participating in research projects.

Last updated on 04-27-20

Selected Full-Text Journal Articles

Biological and clinical manifestations of juvenile Huntington's disease: a retrospective analysis

Fusilli C, Migliore S, Mazza T, et al. Biological and clinical manifestations of juvenile Huntington's disease: a retrospective analysis. The Lancet Neurology. November, 2018; 17(11):986-993.

Last updated on 04-27-20

Name: Huntington's Disease Society of America 505 Eighth Ave, Suite 902
New York, NY, 10018, United States
Phone: (212) 242-1968 Toll Free: (800) 345-HDSA (4372) Email: hdsainfo@hdsa.org Url: http://www.hdsa.org/
Name: International Huntington Association Callunahof 8 Harfsen, Intl 7217 ST
United Kingdom
Phone: 31-573-431595 Email: iha@huntington-assoc.com Url: http://www.huntington-disease.org
Name: Huntington Society of Canada 151 Frederick St, Suite 400 Kitchner, Ontario, Intl N2H 2M2
Phone: 519-749-7063 Toll Free: 800-998-7398 Fax : (519) 749-8965 Email: info@huntingtonsociety.ca/ Url: http://www.huntingtonsociety.ca/
Name: Hereditary Disease Foundation 601 West 168th Street Suite 54
New York, NY, 10032, United States
Phone: 212-928-2172 Fax : 212-928-2172 Email: cures@hdfoundation.org Url: http://www.hdfoundation.org
Name: HOPES Url: http://hopes.stanford.edu
Name: Huntington's Disease Youth Organization HDYO PO Box #272185
Boca Raton, FL, 33486,
Email: info@hdyo.org Url: https://en.hdyo.org/

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The RareGuru disease database is regularly updated using data generously provided by GARD, the United States Genetic and Rare Disease Information Center.

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