Huntington disease how does a person inherit it

People at-risk for the disease face a difficult choice about genetic testing for HD. Some see no benefit in knowing that they will someday develop the disease. Others want an end to uncertainty to make informed choices. The symptoms of Juvenile HD JHD are somewhat different than adult onset HD and may include stiff or awkward walking, increased clumsiness or changes in speech.

An affected person usually inherits the altered gene from one affected parent. In rare cases, an individual with Huntington disease does not have a parent with the disorder.

As the altered HTT gene is passed from one generation to the next, the size of the CAG trinucleotide repeat often increases in size. A larger number of repeats is usually associated with an earlier onset of signs and symptoms. This phenomenon is called anticipation. People with the adult-onset form of Huntington disease typically have 40 to 50 CAG repeats in the HTT gene, while people with the juvenile form of the disorder tend to have more than 60 CAG repeats.

Individuals who have 27 to 35 CAG repeats in the HTT gene do not develop Huntington disease, but they are at risk of having children who will develop the disorder.

As the gene is passed from parent to child, the size of the CAG trinucleotide repeat may lengthen into the range associated with Huntington disease 36 repeats or more. Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. Huntington disease. From Genetics Home Reference. Description Huntington disease is a progressive brain disorder that causes uncontrolled movements, emotional problems, and loss of thinking ability cognition.

Frequency Huntington disease affects an estimated 3 to 7 per , people of European ancestry. Learn more about the gene associated with Huntington disease HTT.

Request an Appointment at Mayo Clinic. Autosomal dominant inheritance pattern Open pop-up dialog box Close. Autosomal dominant inheritance pattern In an autosomal dominant disorder, the mutated gene is a dominant gene located on one of the nonsex chromosomes autosomes. In vitro fertilization Open pop-up dialog box Close. In vitro fertilization During in vitro fertilization, eggs are removed from mature follicles within an ovary A.

Share on: Facebook Twitter. Show references AskMayoExpert. Huntington Disease. Mayo Clinic; Huntington's disease: Hope through research. National Institute of Neurological Disorders and Stroke.

Accessed Feb. Ferri FF. Huntington disease. In: Ferri's Clinical Advisor Elsevier; A physician's guide to the management of Huntington's disease. Huntington's Disease Society of America. National Library of Medicine. Genetics Home Reference. How it's inherited Huntington's disease is caused by a faulty gene that results in parts of the brain becoming gradually damaged over time.

When to get medical advice Speak to your GP for advice if: you're worried you might have symptoms of Huntington's disease — especially if someone in your family has or had it you have a history of the condition in your family and you want to find out if you will get it, too you have a history of the condition in your family and you're planning a pregnancy Your GP may refer you to a specialist for tests to check for Huntington's disease. Treatment and support There's currently no cure for Huntington's disease or any way to stop it getting worse.

But treatment and support can help reduce some of the problems it causes, such as: medicines for depression, mood swings and involuntary movements occupational therapy to help make everyday tasks easier speech and language therapy for feeding and communication problems physiotherapy to help with movement and balance Read more about treatment and support for Huntington's disease. Further information and advice Living with Huntington's disease can be very distressing and frustrating for the person with the condition, as well as their loved ones and carers.

They offer: information about Huntington's disease a specialist advisory service local branches and support groups an online forum Video: Huntington's disease Watch this video for advice on Huntington's disease and the importance of getting tested.