Huntington’s Disease – Symptoms and Causes
Overview
Huntington’s disease is a rare condition that leads to the gradual breakdown of brain cells over time. It affects several aspects of a person’s health, including their movement abilities, cognitive functions, and mental wellbeing.
The disease is typically inherited through a modified gene from one parent. Symptoms of Huntington’s disease commonly emerge when individuals reach their 30s or 40s, though they can appear at any age.
When symptoms develop before age 20, it’s classified as juvenile Huntington’s disease, which may progress more rapidly and present different symptoms than the adult form.
While medications exist to help control Huntington’s disease symptoms, there is currently no treatment that can stop or reverse the progressive decline in physical abilities, thinking skills, and behavioral changes that characterize this condition.
Signs and Symptoms
Movement Problems
People with Huntington’s disease often have trouble controlling their movements. They may have jerky, random movements called chorea that they cannot stop. These movements can affect all parts of the body, including arms, legs, face, and tongue.
Common movement issues include:
- Random jerking or twisting movements
- Stiff muscles or muscle tightening
- Unusual or slow eye movements
- Balance problems and walking difficulties
- Trouble speaking or swallowing
Voluntary movement problems can be even more disruptive than the involuntary ones. These difficulties can make it hard to work, do daily tasks, and live independently.
Thinking Difficulties
Huntington’s disease affects thinking abilities in several ways:
- Organization problems: Difficulty planning or focusing on tasks.
- Mental inflexibility: Getting stuck on certain thoughts or behaviors.
- Poor impulse control: Acting without thinking, having outbursts.
- Reduced self-awareness: Not recognizing their own behaviors.
- Slowed thinking: Taking longer to process information or find words.
- Learning challenges: Trouble taking in new information.
These cognitive changes often worsen as the disease progresses.
Mental Health Issues
Depression is very common in Huntington’s disease. This isn’t just a reaction to having the illness—it happens because the disease damages brain areas that control mood. Signs include:
- Irritability, sadness, or lack of interest
- Pulling away from others
- Sleep problems
- Feeling tired or having low energy
- Thoughts about death or suicide
Other mental health conditions often seen include:
- Obsessive-Compulsive Disorder: Unwanted thoughts and repetitive behaviors.
- Mania: Periods of high energy, impulsive behavior, and inflated self-esteem.
- Bipolar Disorder: Cycles of depression and mania.
Weight loss becomes increasingly common as the disease advances.
Symptoms of Juvenile Huntington’s Disease
When Huntington’s disease affects young people, it shows up differently than in adults.
Behavioral Changes:
- Attention problems
- Declining school performance
- Aggressive or disruptive behavior
Physical Changes:
- Stiff, rigid muscles affecting walking
- Small tremors or shaking
- Frequent falling or clumsiness
- Seizures
Children with juvenile Huntington’s disease often have rigidity as their main movement problem, rather than the jerky movements more common in adults.
When to Contact a Healthcare Provider
If you notice changes in your movements, emotions, or thinking abilities, see a healthcare provider promptly. Many conditions can cause symptoms similar to Huntington’s disease, so getting an accurate diagnosis is important.
What Causes Huntington’s Disease
Huntington’s disease stems from a change in a single gene that parents pass to their children. The disease follows an autosomal dominant inheritance pattern. This means someone needs just one altered copy of the gene to develop the disorder.
People inherit two copies of most genes—one from each parent. When a parent has Huntington’s disease, they have one typical gene and one altered gene. Their children face a 50% chance of receiving the altered gene that causes the disease.
The inheritance pattern works like this:
- Parent with Huntington’s has one altered gene
- Each child has a 50/50 chance of inheriting the altered gene
- If a child receives the altered gene, they will develop the disease
- If a child receives the healthy gene, they won’t develop or pass on the disease
Risk Factors
People with a parent who has Huntington’s disease have a 50% risk of inheriting the gene change that causes this condition.
This means that if one of your parents has Huntington’s disease, you have a one in two chance of developing it yourself.
Complications
Huntington’s disease causes a gradual decline in functioning over time. The disease progression varies for each person, typically lasting between 10 to 30 years from first symptoms until death.
For juvenile Huntington’s disease, this timeline is shorter—usually 10 to 15 years after symptoms appear.
Depression associated with this condition can significantly increase suicide risk. Research indicates this risk may be highest during two specific periods: before receiving an official diagnosis and when the person begins losing their independence.
As the disease advances, individuals will require complete assistance with daily activities.
In late stages, patients are often bedridden and unable to speak, though many retain the ability to understand language and recognize loved ones (though some may lose this ability).
Common causes of death include:
- Pneumonia and other infections
- Injuries from falls
- Complications from swallowing difficulties
While the disease follows a progressive pattern, the specific symptoms and timeline can differ greatly between individuals.
Prevention
For those with a family history of Huntington’s disease, preventing transmission to children is a key concern.
Several options exist to help families make informed decisions.
Genetic Counseling
Meeting with a genetic counselor is an important first step.
These professionals help individuals understand:
- The implications of genetic testing
- The emotional impact of test results
- Available family planning choices
Family Planning Options
Couples concerned about passing on the Huntington gene have several choices:
- Traditional prenatal testing – Testing the fetus during pregnancy for the Huntington gene.
- Alternative conception methods – Using donor eggs or sperm from individuals without the gene.
Advanced Reproductive Technology
In vitro fertilization (IVF) with preimplantation genetic diagnosis offers a scientific approach.
This process works by:
- Collecting eggs from the mother
- Fertilizing them with sperm in a laboratory
- Testing the resulting embryos for the Huntington gene
- Implanting only embryos without the gene into the mother’s uterus
This method allows parents to have biological children without passing on the Huntington gene.
These options give families ways to make reproductive choices that align with their personal values and circumstances.
