Huntingtons Disease (HD)

What is Huntingtons Disease (HD)

Huntingtons disease is a rare genetic condition that weakens nerve cells in certain areas of the brain. The disease gets worse over time. It gradually affects a person’s ability to walk, speak, and think.

Everyone has the HTT gene that plays a role in Huntingtons disease, but people who get the disease have an “expanded” gene. This means that a certain segment of the gene is longer than normal.

Everyone who has this expanded segment eventually gets Huntingtons disease.

Huntingtons Disease is clinically characterized by the presence of a triad composed of chorea, cognitive decline, and a positive family history.

Chorea consists of involuntary, continuous, abrupt, rapid, brief, unsustained, irregular movements that flow randomly from one body part to another. Patients can suppress chorea partially and temporarily and frequently incorporate movements into semipurposeful activities (parakinesia).

Affected patients have a peculiar, irregular gait. Besides chorea, other motor symptoms include dysarthria, dysphagia, postural instability, ataxia, myoclonus, and dystonia.

Motor impersistence is the inability to maintain constant voluntary muscle contraction such as in the characteristic milkmaid’s grip during a handshake.

The tone is decreased, and the deep reflexes are often hung up and pendular.

All patients eventually develop dementia, mainly characterized by loss of recent memory, impairment of judgment, concentration, and acquisition.

Neurobehavioral disturbances occasionally precede motor symptoms and consist of personality changes, apathy, social withdrawal, agitation, impulsiveness, depression, mania, paranoia, delusions, hostility, hallucinations, and psychosis. 

Virtually all patients have a family history of a similar condition transmitted in an autosomal dominant fashion.

Caudate and putamen atrophy on neuroimaging studies is another feature supportive of the diagnosis of Huntingtons disease.

There are two types of Huntingtons disease:

• Adult-onset Huntingtons disease.
  • This is the most common form of the disease.
  • It usually begins at age 35–50 years.
• Early-onset Huntingtons disease, also called juvenile Huntingtons disease.
  • This type is extremely rare.
  • Symptoms begin in childhood or adolescence.

What are the causes?

This condition is caused by an unwanted change (mutation) in the HTT gene. It is passed down through families (inherited).

What increases the risk?

You are more likely to develop this condition if:

• You have a parent with Huntingtons disease.
• You are of European descent.

What are the symptoms of Huntingtons Disease?

The symptoms of this condition get worse over time. At first, symptoms may include:

• Twitching movements.
• Loss of coordination.
• Loss of memory.
• Difficulty making decisions.
• Depression.
• Irritability.

Later symptoms may include:

• Worsening mental condition and abilities.
• More visible jerking and twitching movements.
• Loss of ability to walk or move.
• Not being able to speak.
• Not being able to swallow.

Huntingtons disease is also associated with behavioral health disorders such as depression, bipolar disorder, mania, and obsessive compulsive disorder.

How is Huntingtons Disease diagnosed?

This condition may be diagnosed based on:

• Your symptoms.
• Your family history.
• A physical exam. This is done to check for abnormal movements or reflexes and abnormal speech.
• You may also have other tests to confirm the diagnosis and to rule out other conditions. These may include:
  • Neurological exams. This checks the health of your nerves.
  • Psychological tests. This checks your mental health.
  • Neuropsychological testing. This checks your memory, language, and reasoning skills.
  • Imaging studies of your brain, including CT, MRI, or PET scans.
  • Genetic testing.

How is Huntingtons Disease treated?

There is no cure for Huntingtons disease. Symptoms get progressively worse. Treatment aims to manage symptoms and to provide the best possible quality of life. Treatment may include:

• Taking medicines to help with movement and behavioral health disorders.
• Seeing psychologists and counselors for emotional and mental health support.
• Getting physical therapy, speech therapy, and occupational therapy to help you move, speak, and function as well as possible.

Follow these instructions at home:

• Exercise regularly as told by your health care provider. Being physically fit can make it easier to manage your symptoms. Ask your health care provider what activities are right for you.
• Talk to your health care provider or nutritionist about creating a diet plan. Good nutrition helps to maintain and improve health.
• Take over-the-counter and prescription medicines only as told by your health care provider.
• Have a good support system in place. Consider joining a Huntington’s disease support group.
• Take steps to make your home safe in order to prevent falls. Make sure that:
  • Stairs have railings, and toilets and bathrooms have grab bars.
  • Floors are free from clutter.
  • Anti-slip rugs are installed on floors.
  • Hallways have good lighting.
• Talk with a genetic specialist to help with decisions regarding family planning. Genetic testing for family members (blood relatives) can help:
  • Determine if they carry the gene mutation.
  • Know if they are likely to develop the condition in the future.
  • Know if they can pass the mutation to their children.
• Keep all follow-up visits as told by your health care provider. This is important. This includes visits with your physical and occupational therapists and mental health specialists.

Contact a health care provider if:

• You have new or changing symptoms.
• You have more problems with memory or thinking.
• Your ability to speak, walk, or swallow gets worse.
• You feel that you can no longer care for yourself at home.
• You feel depressed.

Get help right away if you:

• Have thoughts of hurting yourself or others.

If you ever feel like you may hurt yourself or others, or have thoughts about taking your own life, get help right away. You can go to your nearest emergency department or call:

• Your local emergency services (911 in the United States).
• A suicide crisis helpline, such as the National Suicide Prevention Lifeline at 1-800-273-8255. This is open 24 hours a day.

Summary

• Huntingtons disease is a rare genetic condition that weakens nerve cells in certain areas of the brain and gradually affects a person’s ability to walk, speak, and think.
• This condition is caused by an unwanted change (mutation) in the HTT gene. It is passed down through families (inherited).
• The symptoms of this condition get worse over time. At first, symptoms may include twitching movements, loss of coordination, loss of memory, difficulty making decisions, depression, or irritability.
• Later symptoms include worsening mental and physical condition and abilities, such as an inability to walk, speak, or swallow.
• There is no cure for Huntingtons disease. Treatment aims to manage symptoms and to provide the best possible quality of life.