Huntington’s disease is a rare genetic condition characterized by the progressive degeneration of neurons in the brain’s nerve cells, impacting one’s cognitive and physical abilities. It starts with difficulty in making decisions, recurring depression, mood swings, and finally, severe cases of memory loss, slurred speech, and uncontrollable twitching (chorea). In most cases, the symptoms begin around 30-40, and in rare early-onset or juvenile Huntington’s disease can happen in children below the age of 18.

Causes and risk factors
Genetic mutation is the only known cause of Huntington’s Disease. The inheritance of the fourth chromosome carries a mutation on the HD gene, huntingtin, a protein necessary for the proper functioning of the neurons. It helps in the storage of long-term memory. This disease is classified under autosomal dominant disorders, wherein an individual is affected when they carry only one copy of the defective chromosome. This means that the affected individual’s children always carry a 50% chance of inheriting this disease. HD has a prevalence range of 3-7 per 100,000 people, more common in people with European ancestry. Even though both genders are equally inheritable to this condition, studies show women experience higher severity of depression and have shown a quicker decline in cognitive and motor abilities.

Complications


1. Dementia
The slow, progressive loss of memory, thinking, and emotional state is due to the atrophy of neurons throughout the brain. This type of dementia differs from individuals with Alzheimer’s, as the former remembers recent memories and recognizes faces but forgets how to do things (loss of procedural memory).

2. Malnutrition
Due to the weakening of muscles and dysphagia (difficulty in swallowing), individuals find it difficult to chew, eat, or drink, emphasizing the requirement of keeping up the nutritional requirements.

3. Pneumonia and other respiratory complications
An unrelated complication at first that soon became the leading cause of fatality. When food particles or water enter the windpipe due to difficulty swallowing, they may end up in the lungs, causing a severe respiratory infection.

4. Psychological changes
Frequent irritability, unusual eye movements, loss of speech, tremors, depression, psychosis, and loss of sleep.

Diagnosis


1. Imaging tests
The neurologist would suggest an MRI or CT scan to study the progression of the disease. The doctors look out for the development of fluid-filled cavities and shrinking.

2. Neurological exam
Assessing neural capabilities like speech, solving a puzzle, and studying muscle reflexes, balance, and gait.

3. Genetic tests
They are performed to confirm or rule out genetic diseases. The tested parameter is the number of CAG nucleotide repeats in the HD gene. The person is tested positive if the number of CAG repeats is more than 36.

People who have Huntington’s disease require intensive care and surveillance from their families to prevent them from harming themselves as well as others. Once confirmed with their diagnosis, it is necessary to test their children and close relatives to rule out the inherited condition. With genetic diseases gaining the interest of biotechnologists daily, there is a beacon of hope for getting a complete cure for various genetic diseases.

It is important to note that there is no complete cure for Huntington’s, but early detection followed by treatment and physical therapies may reduce the symptoms.