Huntington's Disease
An inherited disorder causing progressive breakdown of brain nerve cells
Quick Facts
- Type: Inherited neurodegenerative disorder
- Cause: A change in the HTT gene
- Inheritance: Autosomal dominant (50% chance to a child)
- Hallmark feature: Chorea (involuntary, dance-like movements)
Overview
Huntington's disease is an inherited condition in which certain nerve cells in the brain gradually deteriorate and die. This breakdown affects areas that control movement, thinking, and emotion, leading to a combination of physical, cognitive, and psychiatric changes that worsen over time.
The disease is caused by a single faulty gene that is passed down through families. Symptoms most often appear in mid-adulthood, usually between the ages of 30 and 50, although a rarer juvenile form can begin in childhood or the teenage years. There is currently no cure, but treatments and supportive care can help manage symptoms and maintain quality of life for many years.
Symptoms
Huntington's disease affects movement, thinking, and mood, and the mix of symptoms varies from person to person. Common features include:
- Movement problems: Involuntary, jerky, dance-like movements called chorea, along with muscle stiffness, slow movement, problems with balance, and difficulty swallowing or speaking.
- Thinking changes: Trouble organizing, focusing, or planning, slowed thinking, and difficulty learning new information.
- Mood and behavior changes: Depression, irritability, anxiety, social withdrawal, and sometimes obsessive thoughts.
Early signs can be subtle, such as small involuntary movements, mood swings, or difficulty concentrating, and they tend to progress gradually over many years.
Causes
Huntington's disease is caused by a change (mutation) in a gene called HTT, which provides instructions for a protein called huntingtin. In people with the disease, a section of this gene is abnormally repeated too many times. This produces a faulty protein that gradually damages brain cells.
The condition is inherited in an autosomal dominant pattern. This means a person needs only one copy of the changed gene to develop the disease, and each child of an affected parent has a 50 percent chance of inheriting it. A person who inherits the gene change will generally develop the disease if they live long enough.
Risk Factors
- Having a parent with Huntington's disease
- Inheriting the expanded HTT gene change
- A family history of the disorder, even if not formally diagnosed
Huntington's disease is not caused by lifestyle or environmental factors. The single risk factor is inheriting the gene change, which is why genetic counseling is an important part of care for affected families.
Diagnosis
Diagnosis is based on a combination of family history, a neurological examination, and genetic testing.
- Neurological and physical exam: Checking movement, reflexes, coordination, balance, and mental function.
- Genetic test: A blood test that looks at the HTT gene can confirm the diagnosis and is highly accurate.
- Brain imaging: MRI or CT scans may show changes in affected brain regions and help rule out other causes.
People with a family history but no symptoms can choose predictive genetic testing, ideally alongside genetic counseling, to learn whether they carry the gene change.
Treatment
There is no cure for Huntington's disease, and no treatment yet stops or reverses its progression. Care focuses on managing symptoms and supporting function and well-being.
- Medications for movement: Certain drugs can help reduce chorea, and others may ease stiffness.
- Medications for mood: Antidepressants and other psychiatric medicines can help with depression, irritability, and anxiety.
- Therapies: Physical, occupational, and speech therapy support movement, daily activities, communication, and safe swallowing.
- Nutrition and supportive care: Help with eating, weight maintenance, and planning for changing needs over time.
A team approach involving neurology, mental health, therapy, and social support works best as the disease progresses.
Prevention
Because Huntington's disease is genetic, it cannot be prevented through lifestyle changes. However, families affected by it have options:
- Genetic counseling to understand inheritance and testing choices
- Predictive genetic testing for at-risk adults who wish to know their status
- Family planning options, including prenatal testing and assisted reproduction, for those who want to avoid passing on the gene
When to See a Doctor
See a doctor if you develop unexplained involuntary movements, growing problems with coordination or memory, or significant mood changes, particularly if Huntington's disease runs in your family. Seek prompt help if you or a loved one experiences:
- Thoughts of self-harm or suicide, which need immediate support and emergency care
- Choking or repeated trouble swallowing
- Falls or rapidly worsening movement or thinking problems
If you are at risk because of a family history, talk with a doctor or genetic counselor about testing and support.
Frequently Asked Questions
Is Huntington's disease inherited?
Yes, Huntington's disease is inherited in an autosomal dominant pattern. Each child of a parent with the disease has a 50 percent chance of inheriting the gene change that causes it.
At what age does Huntington's disease usually start?
Symptoms most often begin in mid-adulthood, typically between the ages of 30 and 50. A rarer juvenile form can begin in childhood or the teenage years.
Can Huntington's disease be cured?
There is currently no cure, and no treatment yet stops the disease from progressing. Medications, therapies, and supportive care can help manage symptoms and maintain quality of life for many years.
How is Huntington's disease diagnosed?
Diagnosis combines a neurological exam, family history, and a genetic blood test that looks at the HTT gene. The genetic test is highly accurate and can confirm the diagnosis or identify the gene change before symptoms appear.
Should I get tested if Huntington's disease runs in my family?
Predictive genetic testing is available for at-risk adults who want to know their status, ideally alongside genetic counseling. The decision is personal, and counseling helps you weigh the emotional and practical implications.
References
- National Institute of Neurological Disorders and Stroke (NINDS). Huntington's Disease.
- Mayo Clinic. Huntington's disease — Symptoms and causes.
- MedlinePlus, U.S. National Library of Medicine. Huntington disease.
- Genetic and Rare Diseases Information Center (GARD), National Institutes of Health.