Huntington Disease

What is huntington disease?

Huntington disease is an inherited condition that gradually damages nerve cells in the brain. Because it is passed down through families and affects the brain, doctors describe it as a hereditary neurodegenerative disorder — “hereditary” meaning it is caused by a change in a gene that can be inherited from a parent, and “neurodegenerative” meaning that nerve cells slowly lose function and die over time. In medical coding systems, huntington disease is listed under ICD-10 code G10.

Many people first ask a simple question: what is huntington disease in everyday terms? It is a condition that affects three main areas of a person’s life — movement, thinking, and mood or behavior. Over the years, people with the condition typically develop involuntary movements, difficulties with memory and decision-making, and emotional changes such as depression or irritability. The condition is progressive, which means symptoms tend to worsen gradually rather than appearing all at once.

Huntington disease usually begins in mid-adulthood, most often between the ages of 30 and 50, although it can start earlier or later. A less common form, called juvenile huntington disease, begins before age 20 and often looks somewhat different from the adult form. The condition affects men and women in roughly equal numbers and occurs in populations around the world, although how common it is varies from region to region.

Because a parent with the altered gene has a 50 percent chance of passing it to each child, huntington disease often affects several generations of the same family. This family pattern is one of the most important clues doctors use when considering the diagnosis.

Symptoms of huntington disease

Huntington disease symptoms usually develop slowly and can look different from one person to another, even within the same family. Doctors often group the symptoms into three categories: movement problems, thinking (cognitive) problems, and emotional or psychiatric problems. In many cases, subtle mood or thinking changes appear years before the movement problems that most people associate with the condition.

Common symptoms

• Involuntary movements (chorea): brief, irregular, dance-like movements of the face, arms, legs, or trunk that a person cannot fully control. “Chorea” comes from the Greek word for dance.
• Clumsiness and balance problems: frequent stumbling, dropping objects, or an unsteady walk.
• Slowed or rigid movements: especially in later stages or in the juvenile form, muscles may become stiff rather than overly mobile.
• Difficulty with speech and swallowing: speech may become slurred or hard to understand, and swallowing may become unsafe over time.
• Trouble with planning and organizing: difficulty starting tasks, staying focused, or making decisions.
• Memory and learning difficulties: often milder early on than in conditions such as Alzheimer disease, but they tend to worsen gradually.
• Mood changes: depression, irritability, anxiety, apathy (loss of interest or motivation), and sometimes obsessive or impulsive behavior.
• Sleep disturbances and weight loss: many people burn more energy because of constant movement and may lose weight despite eating well.

How symptoms change by stage

In the early stage, changes are often subtle. A person may seem more forgetful, irritable, or restless, and small involuntary movements may be mistaken for fidgeting or nervousness. Many people continue working and living independently at this stage.

In the middle stage, involuntary movements usually become more obvious and daily tasks such as dressing, cooking, and managing money become harder. Speech and swallowing difficulties often begin, and emotional symptoms may become more pronounced. Most people need increasing help with everyday activities.

In the late stage, chorea may actually decrease while stiffness and slowness increase. Most people at this stage need full-time care. Speech may be very limited, although understanding often remains better than the person’s ability to respond. Swallowing problems raise the risk of choking and of pneumonia caused by food or liquid entering the lungs (aspiration pneumonia).

Juvenile huntington disease

When symptoms begin before age 20, the picture is often different. Stiffness, slowness, declining school performance, and seizures (episodes of abnormal electrical activity in the brain) are more common in young people, while the classic dance-like movements may be less prominent. Juvenile huntington disease often progresses more quickly than the adult form.

Causes and risk factors

Huntington disease causes are well understood at the genetic level, which sets it apart from many other brain conditions. The condition is caused by a change (mutation) in a single gene called the HTT gene, which carries the instructions for a protein called huntingtin.

Inside this gene, a short section of the genetic code — a sequence of three chemical “letters” known as a CAG repeat — is normally repeated a limited number of times. In people with huntington disease, this section is repeated too many times. The expanded gene produces an abnormal form of the huntingtin protein, which gradually damages nerve cells, particularly in deep brain regions called the basal ganglia that help control movement, and in areas of the cortex involved in thinking and behavior.

How it is inherited

• Autosomal dominant inheritance: a person needs only one copy of the altered gene, from either parent, to develop the condition. Each child of an affected parent has a 50 percent chance of inheriting it.
• It affects both sexes: the gene is not on the sex chromosomes, so sons and daughters are at equal risk.
• Repeat length matters: in general, a larger number of CAG repeats is associated with earlier onset of symptoms, although the relationship is not exact and cannot precisely predict when symptoms will begin.
• New mutations are uncommon: most people with huntington disease have an affected parent, but occasionally the condition appears in a family with no known history, sometimes because a parent had a borderline repeat number that expanded when passed to the child.

The main risk factor is having a parent with huntington disease or with the expanded gene. Lifestyle factors such as diet, exercise, or environment do not cause the condition, although general health can influence how well a person copes with symptoms. People who carry the expanded gene will, in almost all cases, eventually develop symptoms if they live long enough, which is why genetic counseling is a central part of care for affected families.

Diagnosis

Huntington disease diagnosis is based on a combination of the person’s symptoms, the family history, a neurological examination, and — most definitively — a genetic test.

Clinical evaluation

A neurologist (a doctor who specializes in conditions of the brain and nervous system) will ask detailed questions about symptoms, when they began, and how they have changed. The doctor will also ask about relatives who may have had similar movement, thinking, or psychiatric problems, since a family pattern is an important clue. The physical examination focuses on movement, coordination, reflexes, eye movements, speech, and walking. Standardized rating scales are often used to measure the severity of motor, cognitive, and behavioral symptoms and to track changes over time.

Genetic testing

The definitive test is a blood test that counts the number of CAG repeats in the HTT gene. If the repeat number is in the expanded range, the diagnosis of huntington disease is confirmed in a person who has typical symptoms. Genetic testing is also available to adults who have a family history but no symptoms yet; this is called predictive testing. Because a positive result has major emotional, family, and practical implications, predictive testing is done together with genetic counseling — structured sessions with a trained professional who explains what the results can and cannot tell you and helps you think through the decision. Testing children who have no symptoms is generally not recommended, so that they can make their own informed choice as adults.

Imaging and other tests

Brain imaging, such as magnetic resonance imaging (MRI) or computed tomography (CT), may show shrinkage of specific deep brain structures, particularly the caudate nucleus, as the disease progresses. Imaging is not required to confirm the diagnosis when genetic testing is available, but it can help rule out other conditions that cause similar symptoms, such as strokes or tumors. Doctors may also order blood tests to exclude other causes of movement or psychiatric problems, and neuropsychological testing — a detailed assessment of memory, attention, and reasoning — to document cognitive changes.

At large hospital groups such as Acibadem, huntington disease is typically evaluated and followed within the neurology department, often together with genetics, psychiatry, and rehabilitation specialists.

Treatment options

There is currently no treatment that cures huntington disease or reliably stops it from progressing. However, huntington disease treatment can ease many symptoms, protect safety, and support quality of life. Care is usually provided by a multidisciplinary team — a group of professionals from different fields working together — and the treatment plan changes as the condition evolves.

Medications for movement symptoms

• Medicines for chorea: drugs known as vesicular monoamine transporter 2 (VMAT2) inhibitors, such as tetrabenazine and related medicines, can reduce involuntary movements in many people. They require careful monitoring because they can worsen depression or cause drowsiness in some patients.
• Certain antipsychotic medicines: these may be used to reduce chorea, particularly when a person also has agitation, irritability, or psychotic symptoms such as hallucinations.
• Muscle-relaxing medicines: in later stages or in juvenile cases, medicines that ease stiffness may be considered.

Medications for mood and behavior

Depression, anxiety, irritability, and obsessive behaviors are common and often respond to standard psychiatric treatments, including antidepressants and mood-stabilizing medicines, combined with counseling or psychotherapy where appropriate. Treating mood symptoms is a priority, because depression in huntington disease is both common and treatable, and because the risk of suicidal thoughts is higher than in the general population.

Supportive and rehabilitative care

• Physical therapy: exercises to maintain strength, balance, and mobility, and to reduce the risk of falls.
• Occupational therapy: practical strategies and equipment to make daily tasks such as eating, dressing, and bathing safer and easier.
• Speech and language therapy: techniques to keep speech understandable for as long as possible and to manage swallowing difficulties safely; therapists may also recommend communication aids.
• Nutritional support: people with huntington disease often need more calories than expected. A dietitian can help adjust food texture and calorie content. In advanced stages, some families and doctors discuss feeding tubes; this is a personal decision made together with the care team.
• Psychological and social support: counseling for the patient and family, support groups, and planning for future care needs.

Procedures, surgery, and research

Surgery does not play a routine role in huntington disease. Unlike in Parkinson disease, procedures such as deep brain stimulation are not standard treatment, although they have been studied in selected cases. Research into disease-modifying treatments — including gene-targeting approaches designed to lower the amount of abnormal huntingtin protein — is active and ongoing, and clinical trials may be an option for some patients. Your doctor may discuss whether any trial is appropriate for your situation; no experimental approach should be assumed to work until proven in studies.

Watchful waiting for gene carriers

People who carry the expanded gene but have no symptoms do not need medication. Care at this stage usually means regular check-ups, attention to mental health, healthy lifestyle habits, and genetic counseling regarding family planning, which may include discussion of reproductive options.

Living with huntington disease and outlook

Huntington disease is a lifelong, progressive condition, and it is natural to have questions about what the future may hold. On average, people live for one to two decades after motor symptoms begin, although this varies widely from person to person and cannot be predicted precisely for any individual. The juvenile form often progresses more quickly. In later stages, complications such as swallowing problems, infections, and injuries from falls become the main medical concerns.

Although the disease cannot currently be stopped, many people live meaningful lives for years after diagnosis, especially with good symptom management and support. Practical steps that often help include:

• Building a consistent care team, including a neurologist and therapists who know the condition.
• Establishing routines and simplifying tasks as thinking becomes more effortful.
• Making the home safer to reduce fall and choking risks.
• Addressing depression and anxiety early rather than accepting them as inevitable.
• Planning ahead for legal, financial, and care decisions while the person can fully participate.
• Seeking support for caregivers, whose own health and well-being strongly affect the quality of care at home.

Family members who may carry the gene face their own difficult decisions about testing. Genetic counseling can help each person decide what is right for them; there is no single correct choice, and many at-risk adults choose not to be tested.

Frequently asked questions

What is huntington disease in simple terms?

Huntington disease is an inherited brain condition in which nerve cells gradually stop working and die, leading to involuntary movements, thinking difficulties, and mood changes. It is caused by a change in a single gene, and a parent who carries the gene has a 50 percent chance of passing it to each child. Symptoms most often begin between the ages of 30 and 50 and worsen slowly over many years.

Can huntington disease be cured?

At present, there is no cure for huntington disease and no treatment proven to stop it from progressing. However, many of the symptoms — including involuntary movements, depression, and anxiety — can often be eased with medication and supportive therapies. Research into treatments that target the underlying genetic cause is ongoing, and your doctor can tell you whether any clinical trials might be relevant to you.

How serious is huntington disease?

Huntington disease is a serious, progressive condition that eventually affects a person’s ability to move, communicate, and care for themselves. The pace of decline varies considerably between individuals, and many people remain independent for years after diagnosis. With coordinated medical care and family support, symptoms can be managed and complications reduced, but the condition does shorten life expectancy in most cases.

What are the first huntington disease symptoms?

The earliest signs are often subtle and easy to overlook. They may include small involuntary movements or fidgeting, clumsiness, difficulty concentrating or organizing tasks, irritability, or low mood. Because these changes can have many other causes, only a medical evaluation — usually including genetic testing in someone with a family history — can determine whether they are related to huntington disease.

How is huntington disease diagnosed?

Diagnosis usually combines a neurological examination, a review of family history, and a blood test that counts the CAG repeats in the HTT gene. A repeat number in the expanded range confirms the diagnosis in a person with typical symptoms. Brain imaging such as MRI may be used to rule out other conditions, and adults with a family history can request predictive testing with genetic counseling before symptoms appear.

If my parent has huntington disease, will I get it?

Each child of a parent with huntington disease has a 50 percent chance of inheriting the expanded gene. Someone who inherits it will, in almost all cases, eventually develop symptoms, while someone who does not inherit it will not develop the condition and cannot pass it on. Genetic counseling can help you understand your personal situation and decide whether testing is right for you.

Can lifestyle changes slow huntington disease?

No lifestyle change has been proven to slow the underlying disease process. Even so, regular physical activity, good nutrition, adequate sleep, and treatment of depression may help people function better and cope with symptoms. Maintaining body weight is often important, because many people with the condition burn extra calories. Discuss any exercise or diet plan with your care team so it can be adapted safely as the condition changes.

When to see a doctor

If you have a family history of huntington disease and notice new movement, thinking, or mood changes in yourself or a relative, it is reasonable to seek an evaluation by a neurologist. People already diagnosed should keep regular follow-up appointments so treatment can be adjusted as symptoms change. Departments of neurology, such as those at Acibadem, coordinate this kind of long-term follow-up together with genetics and rehabilitation services.

Seek prompt medical attention if any of the following occur:

• Thoughts of self-harm or suicide: this is a medical emergency; urgent help should be sought immediately.
• Choking episodes or coughing during meals: these may signal unsafe swallowing and a risk of food entering the lungs.
• Fever with cough or breathing difficulty: possible pneumonia, which needs rapid treatment.
• Repeated falls or a fall with head injury: injuries may be more serious than they first appear.
• Rapid, unexplained weight loss: a sign that nutrition needs urgent attention.
• Sudden confusion, severe agitation, or hallucinations: these may reflect a treatable complication such as infection or a medication side effect.
• A first seizure: especially important in juvenile huntington disease, and always requires medical assessment.
• Severe drowsiness, stiffness, or worsening mood after a medication change: some medicines used for huntington disease need dose adjustment under medical supervision.

This article is for general information only and cannot replace an individual assessment. A doctor who knows your history is the right person to interpret your symptoms and guide your care.