Huntington’s disease, also known as Huntington’s chorea, belongs to the group of neurodegenerative disorders that cause the progressive degeneration of the brain’s nerve cells. It is an inherited disease that can affect various aspects of an individual’s life, including physical movements, cognitive abilities, and emotions. There are two types of Huntington’s disease – Adult onset and Early onset – and there are many early warning signs that manifest differently for different people.

Adult onset
Early symptoms of Adult Onset Huntington’s include:

• Irritability
• Anxiety
• Difficulty in making decisions
• Mood swings
• Uncharacteristic clumsiness
• Unable to balance
• Restlessness
• Forgetfulness
• Memory issues
• Difficulty comprehending new information

As time passes, symptoms may include:

• Muscle rigidity
• Mobility issues
• Cognitive decline
• Paranoia
• Breathing issues
• Involuntary twitching
• Trouble swallowing

Early onset
While Huntington’s itself is a rare condition, early onset of the disease is even less common, with symptoms usually starting to appear in childhood or adolescence. Also called Juvenile Onset Huntington’s Disease (JHD), it affects children and teenagers.

Symptoms include:

• Drooling
• Clumsiness
• Changes in personality
• Slurred speech
• Rigid muscles
• Poor school performance that happens suddenly
• The progression rate of JHD is faster than adult onset HD.

Huntington’s disease is caused by a defect in a single gene, marking it as an autosomal dominant disorder. This means that if one parent has the mutated gene, each child has a 50% chance of inheriting it. Individuals with the mutated gene will eventually develop the disease, typically in mid-adulthood, and even pass it on to their children.

Since it is an inherited disease, family history plays a huge role in the diagnosis, along with clinical and laboratory testing.

The symptoms of Huntington’s disease do not show up in the same order for everyone suffering from it. Which symptoms appear first differ from person to person, and the dominance and severity of the symptoms also differ.

Physical symptoms
HD may cause symptoms that affect a person’s balance and gait, as well as cause problems with voluntary and involuntary movements. Some may have difficulty speaking, swallowing, or eating, which could weaken a person’s immune system. Chorea, which is the most common involuntary symptom of adult HD, is uncontrollable movements like jerks and twitches that could affect any part of the body.

Other involuntary symptoms may include loss of coordination, unusual eye movements, and muscle contractions.

Behavioral symptoms
People with Huntington’s disorder could display a series of behavioral symptoms like aggression, hostility, frustration, insomnia, irritability, moodiness, and hypersomnolence.

Cognitive symptoms
These could include memory loss, apathy, hallucinations, lethargy, brain fog, flawed organizational skills, confusion, disorientation, and difficulty multitasking. Cognitive symptoms could worsen over time and could lead to dementia.

The genetic mutation that leads to Huntington’s Disease is different as this isn’t an issue of a missing gene or a substitution. It is a copying error where a certain part within chromosome 4 of huntingtin (HTT) is copied many times. With each generation, the number of repeated copies tends to increase.

A diagnosis can be made on the basis of a combination of physical, behavioral, and cognitive symptoms and a confirmed family history of HD. If there is no family history, identifying the symptoms as being caused by HD can be challenging. In such a scenario, a neurologist will be consulted.