Huntington’s disease

Huntington’s disease is a progressive condition that damages nerve cells in the brain over time. It affects movement, thinking skills, and emotional well-being.

Although rare, the disease is usually inherited from a parent who carries a genetic mutation.

Symptoms may appear at any age, but most people start noticing them in their 30s or 40s. When symptoms begin before age 20, the condition is called juvenile Huntington’s disease, which often progresses more quickly and may present with different signs.

While medications can ease certain symptoms, no treatment can fully stop or reverse the decline in physical, mental, and behavioral function caused by the disease.

Symptoms

Huntington’s disease can affect movement, cognition, and mental health. The type and severity of symptoms vary widely among individuals, and they may worsen or change as the disease progresses.

Movement-related symptoms

The disorder often leads to involuntary or impaired voluntary movements. These may include:

• Sudden jerking or twisting movements (chorea).
• Stiff or contracted muscles.
• Unusual or slow eye movements.
• Difficulty walking, balancing, or maintaining posture.
• Trouble speaking or swallowing.

Loss of voluntary movement control can be even more disabling than involuntary movements, as it interferes with independence, work, communication, and daily activities.

Cognitive symptoms

Decline in mental skills is common and may include:

• Difficulty organizing or focusing.
• Getting stuck on thoughts or behaviors (perseveration).
• Poor impulse control, which may lead to inappropriate actions.
• Reduced awareness of personal behavior and abilities.
• Slowed thinking or trouble finding words.
• Struggles with learning new information.

Mental health symptoms

Depression is one of the most common psychiatric effects, caused by changes in brain function rather than just the stress of diagnosis. Signs may include:

• Persistent sadness, irritability, or apathy.
• Withdrawal from social activities.
• Fatigue, low energy, or sleep problems.
• Suicidal thoughts.

Other possible mental health issues include:

• Obsessive-compulsive disorder (OCD).
• Mania, involving extreme mood elevation and impulsive behavior.
• Bipolar disorder, with alternating periods of depression and mania.

Weight loss often occurs, particularly in the later stages of the disease.

Juvenile Huntington’s Disease

When the condition develops in children or teens, symptoms may differ:

Behavioral changes

• Difficulty focusing.
• Drop in school performance.
• Aggressive or disruptive behaviors.

Physical changes

• Muscle stiffness affecting walking.
• Tremors or small involuntary movements.
• Frequent falls or clumsiness.
• Seizures.

When to See a Doctor

Consult a healthcare professional if you experience unexplained changes in movement, mood, or cognitive function. Because these signs can also be linked to other conditions, a thorough evaluation is important.

Causes

Huntington’s disease results from a mutation in a single gene, passed from an affected parent. It follows an autosomal dominant inheritance pattern, meaning that inheriting just one copy of the faulty gene is enough to develop the disease.

Each child of a parent with Huntington’s has a 50% chance of inheriting the defective gene.

Risk Factors

The only known risk factor is having a parent with Huntington’s disease.

Complications

Once symptoms begin, a person’s abilities gradually decline. Progression speed varies, but most people live 10 to 30 years after the first signs appear. Juvenile cases often progress faster, leading to death within 10 to 15 years.

Possible complications include:

• Increased risk of suicide, especially around diagnosis or loss of independence.
• Dependence on full-time care in later stages.
• Bed confinement and loss of speech, though many people retain awareness of loved ones.

The most common causes of death include:

• Pneumonia and infections.
• Injuries from falls.
• Complications from swallowing difficulties.

Prevention

People with a family history of Huntington’s often worry about passing the condition to children. Options include:

• Genetic counseling to understand risks.
• Genetic testing to determine carrier status.
• Prenatal testing or in vitro fertilization (IVF) with genetic screening to ensure embryos without the Huntington’s gene are implanted.
• Use of donor eggs or sperm if parents wish to avoid passing on the mutation.

These choices involve difficult emotional and ethical decisions, and support from medical professionals and counselors can help guide families.