Huntington’s disease is an incurable, hereditary brain disorder that damages brain cells. It has a wide-ranging impact, affecting movement, thinking, and mood.

Huntington’s disease happens when a gene mutation causes toxic proteins to collect in the brain.

The condition affects 3–7 in every 100,000 people of Western European ancestry. According to Genetics Home Reference, it appears to be less common in people of Japanese, Chinese, and African descent.

The first signs normally appear in people aged 30–50.

Huntington’s disease is a neurological condition. It is an inherited disease that results from a gene mutation. Toxic proteins collect in the brain and cause damage, leading to neurological symptoms.

As the disease affects different parts of the brain, it impacts movement, behavior, and cognition. It becomes harder to walk, think, reason, swallow, and talk. Eventually, the person will need full-time care. The condition or its complications can be fatal.

There is currently no cure, but treatment can help with symptoms.

Signs and symptoms are most likely to appear in people aged 30–50 but can occur at any age.

Key symptoms include:

The development of symptoms can vary between individuals. Some will experience depression first and then changes in motor skills. Mood changes and unusual behavior are common early signs.

Early signs and symptoms

A doctor may not recognize the early symptoms if none of the person’s family members have previously received a diagnosis of Huntington’s disease. It can take time to reach a diagnosis.

Initial signs and symptoms may include:

  • slight uncontrollable movements
  • small changes in coordination and clumsiness
  • stumbling
  • slight mood and emotional changes
  • difficulty focusing and functioning at school or work
  • lapses in short-term memory
  • depression
  • irritability

The person may also lose motivation and focus, appearing lethargic and lacking in initiative.

Other possible early signs of Huntington’s disease may include dropping things and forgetting people’s names. However, most people do these things occasionally. Over time, these symptoms become more severe in a person with Huntington’s.

The middle and later stages

As the disease progresses, it includes more physical changes, loss of motion control, and emotional and cognitive changes.

Physical changes

The person may experience:

  • difficulty speaking, including problems with finding words and slurring
  • weight loss, leading to weakness
  • difficulty eating and swallowing, as the muscles in the mouth and diaphragm may lose function
  • risk of choking, especially in later stages

There may be uncontrollable body movements, including:

  • movements of the face
  • jerking of parts of the face and the head
  • flicking or fidgety movements of the arms, legs, and body
  • lurching and stumbling

Over time, uncontrollable movements occur more often and usually with more intensity. Eventually, they may become slower as the muscles become more rigid.

Emotional changes

There are two categories of emotional and psychological symptoms of Huntington’s.

The first category involves developing mental illnesses that are also common among people who do not have the disease. About 40% of people with Huntington’s will develop conditions such as obsessive-compulsive disorder, mania, or delusional disorders.

The second category involves mental state changes caused by brain alterations as a result of Huntington’s itself. These can include:

  • aggression
  • anger
  • antisocial behavior
  • apathy
  • depression
  • excitement
  • frustration
  • increasingly apparent lack of emotion
  • moodiness
  • stubbornness
  • cognitive changes

There may also be:

  • a loss of initiative
  • a reduction of organizational skills
  • disorientation
  • difficulty focusing
  • problems with multitasking

According to the Huntington’s Disease Society of America (HDSA), the risk of suicide is increased in people with Huntington’s by up to 10 times the national average due to cognitive changes, including disinhibition and impulsivity. It recommends that loved ones and caregivers of people with the condition are aware of the signs of suicide ideation.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The National Suicide Prevention Lifeline is available 24 hours per day at 800-273-8255. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 800-273-8255.

Click here for more links and local resources.

The later stage

Eventually, the person will no longer be able to walk or talk and will need full nursing care.

However, they will usually understand most of what they hear and be aware of their surroundings, as well as friends and family members.

The declining ability to do things that hay have once been easy can lead to frustration and depression.

Weight loss can make symptoms worse and weaken the patient’s immune system, making them more vulnerable to infections and other complications.

Huntington’s disease itself is not usually fatal, but it can lead to choking, pneumonia, or other infections that can lead to death.

Huntington’s disease results from the mutation of a gene on chromosome number 4.

A typical copy of the gene produces huntingtin (HTT), a protein. The gene with the mutation is larger than it should be. This leads to excessive production of cytosine, adenine, and guanine (CAG), the building blocks of DNA. Normally, CAG repeats 36 times or less, but in Huntington’s disease, it repeats 36 times or more.

This change results in a larger form of the HTT protein, which is toxic. As the toxic protein accumulates in the brain, it begins to damage certain brain cells.

If the repetition is 36–39, the person could develop Huntington’s disease but may not. If it repeats 40 times or more, a person will almost certainly develop the condition.

How is it passed on?

Huntington’s disease is an autosomal dominant disorder. This means a person can have it if they inherit only one copy of the gene with the mutation from either parent.

A person with the gene mutation has one typical copy of the gene and one mutated copy. Any offspring will inherit either the typical copy or the mutated one. The child who inherits the typical copy will not develop Huntington’s disease. The child who inherits the copy with the mutation will.

Each child has a 50% chance of inheriting the gene mutation. If they inherit the gene with the mutation, each of their children will have a 50% chance of inheriting it. It can affect several generations.

A person who does not inherit the gene mutation will not develop the disease and cannot pass it on to their children. A child who inherits the gene mutation will develop Huntington’s if they reach the age when symptoms are due to emerge. Up to 10% of people with the gene mutation develop symptoms before age 20, and around 4–11% develop them after 60.

If symptoms start before a person is 20, a doctor will diagnose them with juvenile Huntington’s disease.

The physical symptoms of the juvenile version of the disease tend to be different and can include leg stiffness, tremors, and regression in learning.

This version of the disease usually progresses more rapidly. It may be fatal within 10 years of a diagnosis. The cause of death is often a complication, such as pneumonia or choking.

Huntington’s disease is currently incurable. Treatment cannot reverse its progression or slow it down.

However, medication and other therapies can help manage some symptoms.

Medications

Currently, the Food and Drug Administration (FDA) has approved two medications specifically to treat Huntington’s symptoms.

Tetrabenazine (Xenazine) treats the jerky, involuntary movements or chorea that can occur with Huntington’s disease. Side effects include depression and suicidal thoughts or actions.

Deutetrabenazine (Austedo) also treats involuntary movements, particularly those that may occur in the face and tongue.

If a person has signs of depression or mood changes when taking these drugs, they should contact a doctor at once. Neither drug is suitable for anyone who already has a diagnosis of depression, especially with suicidal thoughts. A person should speak to their doctor to make sure there are no other medical reasons they may need to avoid these drugs.

A variety of other drugs that may benefit people with Huntington’s disease are currently undergoing clinical trials.

Examples of other drugs that may help control movements, outbursts, and hallucinations may include:

Adverse effects include sedation, stiffness, and rigidity.

For depression and some obsessive-compulsive features, examples of medications a doctor may prescribe include:

Speech therapy

Huntington’s disease can cause severe problems with controlling the muscles of the throat and mouth. This makes it difficult for the person to speak, swallow, and eat.

Speech therapy may help a person improve these skills and reduce the resulting challenges.

A speech therapist can also teach a non-verbal person how to communicate without speaking, for example, by using a board with images of items and activities in everyday life.

Physical and occupational therapy

A physical therapist can help improve a person’s muscle strength and flexibility, improving balance and reducing the risk of falling.

The therapist may design exercises for the person that fit their level of ability and that they can repeat regularly and adjust them as the person’s physical state changes. The therapist can also advise the person on using supporting devices such as a wheelchair or walker.

The occupational therapist can assist the person with additional supportive devices that help with daily functioning, such as handrails throughout the home, specialized eating and drinking utensils, and devices that help a person shower or dress.

To diagnose Huntington’s disease, the doctor will examine the person and ask about their family and medical history and any symptoms, such as recent emotional changes.

If they believe a person may have Huntington’s, they will refer them to a neurologist.

Doctors sometimes recommend imaging tests, such as a CT or MRI scan. These can identify changes in brain structure and help rule out other disorders.

Genetic testing may also help confirm a diagnosis.

Genetic testing for Huntington’s disease became possible in 1993. Anyone with a family history of the disease can ask a doctor about genetic testing to determine whether they carry the gene mutation.

Some people prefer to find out if they have the gene and are likely to develop symptoms, while others would rather not know. A genetic counselor can help with making the decision.

Huntington’s, genetics, and pregnancy

If a couple wishes to have a child and one parent has the gene mutation, they can have in-vitro fertilization (IVF) treatment.

The embryo is then genetically tested in a laboratory and doctors only implant it if it does not have the gene mutation.

A fetus can also undergo genetic testing during gestation if there is a family history of the disease. Doctors do this using a chorionic villus sample, a tissue sample from the placenta, at 10–11 weeks, or through an amniocentesis at 14–18 weeks.

Huntington’s disease can have a significant emotional, mental, social, and economic impact on the life of an individual and their loved ones. Most people with this condition will live for 10–30 years after a diagnosis.

There is currently no cure, but treatment can help people manage the condition and improve their quality of life.

In the future, scientists hope that gene therapy will find a solution to this condition. Researchers have been looking for ways to use gene therapy to cure, slow, or prevent Huntington’s.

In 2017, scientists from Emory University suggested that CRISPR-Cas9 techniques, which involve “cutting and pasting” DNA, could help prevent Huntington’s disease in the future.

Experiments in mice have shown “significant improvements” after 3 weeks. Most traces of the damaging protein had gone, and the nerve cells showed signs of healing themselves.

Additional studies have shown that a similar approach may be successful on a cellular level, but more research is needed to determine how doctors can apply this to treat people with Huntington’s disease.

Meanwhile, organizations such as the HDSA offer support for people with the condition and their families.