What Is Huntington's Disease?

Huntington’s disease is a hereditary degenerative neurological disease that causes behavioral changes and involuntary movements, with noticeable effects usually beginning between age 30 to 50. There is no cure for the condition, but some symptoms can be reduced with medication.

Living with Huntington’s disease poses a number of challenges for the person who has the condition and their family. The disease progressively worsens, resulting in deterioration of self-care, and death typically occurs between 10 to 30 years after diagnosis. 

Huntington's Disease Symptoms

The symptoms of Huntington’s disease include dementia, involuntary movements, and movement impairment. The symptoms of Huntington's disease slowly get worse over time and tend to vary based on the disease stage:

Early Stage

Early symptoms of HD include:

• Difficulty learning new things or making decisions
• Problems with driving
• Irritability, mood swings
• Involuntary movement or twitching
• Coordination challenges
• Short-term memory problems

Middle Stage

As Huntington’s disease progresses into the middle stage, the person has trouble with swallowing, speaking, walking, memory and concentrating on tasks. Weight loss and malnutrition is common.

The classic writhing movements (chorea) of HD may become very pronounced and interfere significantly with daily functioning.

The person may also develop some obsessive behaviors.

Late Stage

Late-stage Huntington’s disease symptoms consist of the inability to walk or talk. Full care from a caregiver is required.

Instead of chorea, a person may have rigidity, slowed movements (called bradykinesia), and dystonia. People who have late-stage HD are at high risk for choking.

Early Onset 

There is a juvenile form of Huntington’s disease that can begin during childhood or adolescence. The symptoms of the juvenile form are similar to those of the adult form, but they generally progress more rapidly, and seizures are common as well.

Complications 

Huntington’s disease is a neurological condition, and the neurological effects usually lead to systemic complications, such as malnutrition, infections, and falling and other injuries. It is these complications that typically lead to death in Huntington’s disease.

Causes 

Huntington’s disease is inherited in an autosomal dominant pattern. If a person inherits the gene that causes the disease from either parent, they will develop the condition. 

The condition occurs due to a mutation (abnormality) on chromosome 4 in the location of the HTT gene. The genetic defect is a CAG repeat, which is produced by extra nucleotides in the DNA molecule. This gene codes for the huntingtin protein. The exact role of this protein is not known. 

The effects of the disease are believed to be associated with the deterioration of neurons in the brain. This deterioration affects many areas of the cerebral cortex, but it is most noticeable in the caudate, an area of the brain that is involved with memory and movement.

Huntington’s disease is a degenerative condition, and researchers suggest that it could be associated with oxidative stress-induced damage to the brain. 

Diagnosis 

Huntington’s disease is diagnosed based on clinical symptoms, family history, and genetic testing. Your healthcare provider will review your symptoms with you, and, if possible, may ask your close family members about your symptoms as well. 

Your physical examination will include a full neurological and cognitive examination. If you have Huntington’s disease, your physical examination can reveal impairments such as lack of physical balance and involuntary movements. You may also have a characteristic pattern of walking, in which you take long steps.

There are no diagnostic tests besides the genetic test that support a diagnosis of Huntington’s disease. For example, while the condition is associated with atrophy in areas of brain, especially in the cerebral cortex, this is not a consistent enough finding to be considered helpful in diagnosis.

If your genetic test is negative (you do not have the gene for Huntington’s disease), you would have other tests to determine the cause of your symptoms. These tests can include blood tests, brain imaging studies, and/or nerve conduction studies. 

Treatment 

If you have Huntington’s disease, your treatment will be focused on controlling your symptoms. There is no medication that can stop or reverse the progression of Huntington’s disease. 

You might need to participate in therapy, such as physical therapy to optimize your walking and coordination and swallow therapy to help you chew, eat, and swallow safely. Over time, as these abilities decline, you will eventually experience more substantial effects of your condition, but therapy may delay some of the impact on your day-to-day life. 

You may benefit from medication to reduce your involuntary muscle movements and muscle stiffness. And you might also benefit from antipsychotic treatment to manage your hallucinations. 

Additionally, you would need treatment for any complications that arise, such as nutritional supplements if you can’t eat adequately, or antibiotics if you develop an infection. 

Prognosis

The prognosis of Huntington’s disease is poor at this time. The average life expectancy following diagnosis ranges from 10 to 20 years.

Coping 

Living with Huntington’s disease can be difficult for you and your loved ones. The challenges begin when you learn that you could have inherited Huntington’s disease and continue with diagnosis of the condition and as the disease progresses. 

Genetic Counseling

The decision about genetic testing is a complex and emotional issue. You will likely meet with a genetic counselor as you are deciding whether or not to have a genetic test. If you decide to have a genetic test before any symptoms emerge, you will know definitively whether you will develop the condition or not.

And if you decide not to have a genetic test, you will be living with uncertainty for most of your life about whether you will develop Huntington’s disease. You will need to decide which approach is best for you. 

Care Assistance

You may eventually need assistance with your daily care, and this can involve getting professional help from a caregiver in your home. As the disease progresses, you and your family might decide that it could be safer for you to move to a facility where you can get round the clock medical care, such as in a nursing home. 

Psychological Impact

As you are coping with the anticipation of your disease and the clinical effects of your condition, you might benefit from seeing a therapist to talk about your concerns and feelings. This could also be a valuable resource for your loved ones as well.

Prevention 

There is no way to prevent Huntington’s disease from developing if you have the gene mutation. However, it is possible to get tested to know if you have the mutation. Your results may help you with family planning as you are deciding whether parenting is right for you. 

 A Word From Verywell 

Huntington’s disease is a relatively rare disease, affecting about one in 10,000 people. You might already know that you are at risk of this disease due to your family history, or you could be the first person in your family to be diagnosed with the condition.

Living with Huntington’s disease means that you will have to manage the expectations of developing the condition and planning for your future medical care, while also enjoying the healthy years that you have before the symptoms develop.