Understanding Huntington's disease: Predicting prognosis and life expectancy

Medically reviewed by Paige Henry
Updated January 3, 2024by BetterHelp Editorial Team

Huntington's Disease (HD) is a hereditary neurodegenerative disorder caused by a genetic mutation in the huntingtin gene. The mutation leads to the degeneration of nerve cells in the brain, resulting in movement, cognitive, and psychiatric impairments that worsen over time. The disease often manifests in adulthood, with the onset typically occurring between 30 and 50. However, it may rarely affect children, adolescents, and young adults. 

The symptoms of HD vary from person to person and can include involuntary movements, such as chorea, and difficulties with balance, coordination, and speech. Cognitive impairments can also affect memory, judgment, and decision-making abilities. Psychiatric symptoms such as depression, anxiety, and irritability are also common in people with HD.

Understanding Huntington’s disease

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The prognosis and life expectancy of Huntington's disease can vary based on the age of onset, the severity of symptoms, and the rate of disease progression. For example, people who develop symptoms at a younger age may experience a more rapid progression of the disease and a shorter life expectancy. The severity of symptoms can also affect the prognosis, with more severe symptoms leading to a worse outlook.

There is no cure for HD, but supportive care and symptom management can improve the quality of life for people with the disease. Medications may help individuals manage some of the symptoms of the disease, such as chorea and depression. Physical and occupational therapy can also benefit people with HD, helping them maintain mobility and independence for as long as possible.

What causes Huntington's disease?

Huntington's Disease (HD) is a hereditary neurodegenerative disorder that affects the nervous system, leading to movement, cognitive, and psychiatric impairments. It is caused by a genetic mutation in the huntingtin gene, which leads to the degeneration of nerve cells in the brain.

The huntingtin gene provides instructions for making a protein called huntingtin, which is involved in various cellular functions, including transporting molecules within cells. However, in people with HD, the huntingtin gene contains an abnormally expanded section of DNA, known as a CAG trinucleotide repeat. This expanded repeat process produces an abnormal huntingtin protein, which accumulates in nerve cells and causes them to degenerate.

The exact mechanism by which the abnormal huntingtin protein leads to nerve cell death is not fully understood. However, the protein may interfere with normal cellular processes, leading to oxidative stress, mitochondrial dysfunction, and inflammation, which can contribute to the degeneration of nerve cells.

HD is an autosomal dominant disorder, so a person must only inherit one copy of the mutated huntingtin gene from one parent to develop the disease. Each child of a parent with HD has a 50% chance of inheriting the mutated gene and developing the disease.

The number of CAG repeats in the huntingtin gene is also associated with the age of onset and severity of symptoms of HD. People with fewer than 36 CAG repeats typically do not develop HD, while people with 40 or more repetitions often develop symptoms. The age of onset is often earlier in people with a more significant number of CAG repeats.

Symptoms of Huntington's disease

The symptoms of HD vary from person to person and depend on the stage of the disease. The early symptoms include subtle changes in coordination, mood, and cognition. As the disease progresses, the symptoms become more severe, including involuntary movements, cognitive decline, and psychiatric disturbances.

Advanced symptoms of Huntington's disease

Advanced symptoms of Huntington's Disease (HD) refer to the stage of the disease when the individual experiences a significant decline in their ability to perform daily activities, such as walking, talking, and swallowing. In this stage, the individual requires assistance with most activities of daily living and may become entirely dependent on caregivers.

One of HD's most prominent advanced symptoms is the progressive deterioration of motor skills, which leads to involuntary movements or chorea. These movements may be jerky or writhing and affect the limbs, trunk, face, and tongue. In addition, the individual may also experience muscle rigidity, bradykinesia, and postural instability, like the symptoms of Parkinson's disease.

Individuals may experience cognitive impairment as HD progresses, including memory, attention, and decision-making difficulties. In addition, they may have trouble understanding and processing information, leading to challenges with problem-solving and communication.

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Psychiatric symptoms of Huntington's disease

Psychiatric symptoms are common in advanced HD, including depression, anxiety, apathy, irritability, and aggression. In addition, individuals may experience hallucinations, delusions, and obsessive-compulsive behavior, leading to significant distress for the individual and their caregivers.

Another significantly advanced symptom of HD is dysphagia, or difficulty swallowing, which can lead to aspiration and pneumonia. Individuals with HD may also experience weight loss and malnutrition due to eating and drinking problems.

In addition to these symptoms, individuals with advanced HD may experience urinary incontinence, sleep disturbances, and seizures. As a result, they may become bedridden and require specialized care to prevent pressure ulcers, contractures, and other complications associated with immobility.

The advanced symptoms of HD can vary widely among individuals, and not all individuals experience all symptoms. Additionally, the progression of the disease can be unpredictable, and the duration of the advanced stage can vary from months to years.

How is a diagnosis of Huntington's disease made? 

Diagnosing Huntington's Disease involves genetic testing, neurological examination, and imaging tests like MRI and CT scans. Genetic testing is the most reliable method of diagnosing HD, as it can detect mutations in the huntingtin gene accurately.

Prognosis of Huntington's disease

HD is a progressive disease that worsens over time, leading to significant disability and death. The prognosis of HD varies from person to person and depends on several factors, including the age of onset, symptoms' severity, and progression rate.

Below are further examinations of each factor that may lead to one's prognosis. 

Age of onset

The age of onset is one of the most significant factors that affects the prognosis of HD—the earlier the beginning of the disease, the faster its progression and the worse the outcome. For example, people who develop HD before age 20 may have a more rapid progression and a poorer prognosis than those who develop it in their 40s or 50s.

Severity of symptoms

The severity of the symptoms is another factor that affects the prognosis of HD. People with more severe symptoms, such as significant cognitive and psychiatric impairments, may have a poorer prognosis than those with milder symptoms.

Rate of progression

The disease's progression rate is also an essential factor affecting HD's prognosis. Some people may have a slow disease progression, while others may have a more rapid progression.

Life expectancy for those living with Huntington's

The factors that may impact the life expectancy of someone with Huntington's disease include the following: 

  • The age at which symptoms first appear.
  • The rate of disease progression.
  • The presence of other medical conditions.

On average, individuals with Huntington's disease live for ten to 30 years after the onset of symptoms. However, this is an average estimate, and some individuals may live more or less time. In addition, the severity of symptoms and the rate of disease progression can vary significantly between individuals, making it difficult to predict how long someone will live with Huntington's disease.

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Counseling options 

Therapy may offer several benefits to individuals with Huntington's disease, as it can provide convenient opportunities for care. However, some individuals may struggle to avail of in-person appointments. In these cases, online therapy platforms like BetterHelp may be more convenient.  

Online therapy can be used from the comfort of one's home, which may benefit those with mobility or transportation issues. In addition, online therapy sessions can be scheduled at a convenient time for the individual, which can be helpful for those who may have difficulty traveling to appointments or have other commitments that make it challenging to attend in-person sessions.

While there is limited research on the effectiveness of online therapy for individuals with Huntington's disease, studies on online therapy for other conditions suggest that it can be effective. For example, one study found that online cognitive-behavioral therapy (CBT) was as effective as in-person CBT in treating depression and anxiety in individuals with multiple sclerosis. Additionally, a systematic review of studies on online therapy for depression and anxiety found that it improved overall well-being. Finally, a third study discovered that online cognitive training could improve cognitive function in older persons with mild impairment. 

Takeaway

HD is a progressive disease that affects the nervous system, leading to movement, cognitive, and psychiatric impairments. The prognosis and life expectancy of HD vary from person to person and depend on several factors, including the age of onset, the severity of symptoms, and the rate of progression. 

While there is no cure for HD, early detection, supportive care, and symptom management can improve the quality of life for people with HD. If you are struggling to cope with the symptoms of early HD or are a caregiver seeking mental health support, consider reaching out to a mental health professional online or in your area to get started with therapy. You're not alone, and support is available.

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