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Huntington’s Disease

Huntington’s is a brain disorder that’s progressive in natural, caused by a single defective gene on chromosome 4. Since changes occur within the central region of the brain, individuals experience symptoms related to mood, mobility, and cognition 

What is Huntington’s Disease?

There are 23 human chromosomes and individuals who experience a defective gene on chromosome 4 develop this disease. Since this defect is dominant, in comparison to recessive, anyone that inherits this specific gene will develop Huntington’s in their lifetime. Each child of a parent with Huntington’s has a 50 percent chance of inheriting the disease.

This defective gene offers the blueprint for a protein called huntingtin. Although this protein’s normal function is not full understood, the defective form is what causes Huntington’s. These proteins cause changes in the brain, leading to symptoms such as depression, involuntary movements, and a decline in thinking skills. 

Core Symptoms of Huntington’s Disease

Huntington’s disease can develop fairly early, generally being diagnosed between the ages of 30 and 50. In some cases, symptoms can develop as early as 2 years old or as late as 80 years old. Like most conditions that affect the brain, not everyone will display the exact same symptoms. Symptoms also vary depending on the stage of Huntington’s. You can expect symptoms related to:

  • Emotional distress, including depression, anxiety, apathy, and more.
  • Cognitive decline, as individuals lack focus, being unable to recall information or make decisions.
  • Physical symptoms, including weight-loss, issues with walking, involuntary movements, and lack of coordination.

The Causes of Huntington’s Disease

As mentioned, this disease is reliant on the defective gene which was identified in 1993. In one small section on chromosome 4, there’s a defect involving a specific chemical, more specifically the repeats of that chemical. While focusing on a normal huntingtin gene, there’s 17 to 20 repetitions of this chemical code. In the defective gene, however, there’s 40 repeats or more. This is how genetic testing identifies Huntington’s.

In normal functioning individuals, the function of huntingtin protein isn’t understood. It’s also not known how repeating the chemical code leads to the progression of Huntington’s disease. Researchers are focused on why this occurs, as it may unlock clues regarding other degenerative brain conditions.

Possible Treatment Methods

At this time, there’s no cure for Huntington’s disease. Even if the gene is identified before changes occur, nothing can be done to prevent or slow down the progression of these changes. Like many degenerative brain conditions, treatments focus on managing symptoms.

Individuals may be prescribed certain drugs to help lessen symptoms such as depression, involuntary movements, or anxiety. Since these drugs also create side effects in some patients, not everyone with Huntington’s is treated with medication.

In many cases, individuals need to be patient as their health care team finds the best drugs and the right doses to fit their personal needs. Remember, everyone is unique so what works for one person, may not work for you. Exciting research continues and progress is being made so hopefully better treatment options will be offered in the future.

The Differences Between Alzheimer’s and Huntington’s

Huntington’s is a progressive form of dementia that’s inherited. Although Alzheimer’s can develop due to genetics, it is not a single gene that causes this disease to develop as it does in Huntington’s. When it comes to Alzheimer’s, there’s a gene that places individuals at risk, known as ApoE 4. There’s also a gene that determines the onset of Alzheimer’s will occur, but it is fairly rare.

The onset of these diseases also highly differs, as Huntington’s develops early on. Symptoms typically arise in the late 30s or 40s, but can be seen in adolescence. Early-onset Alzheimer’s can develop around the same time (the late 30s or 40s), however, Alzheimer’s is typically associated with older individuals.

Fast Facts 

  • The disease itself was named after Dr. George Huntington
  • Within the United States, approximately 1 our of every 30,000 people are affected with this disease
  • Physical and speech therapy can improve quality of life
  • Although a genetic test can determine if the defective gene is present, doctor cannot tell when the disease will develop
  • Some Huntington’s patients lose up to 25 percent of their brain cells before they die



Genetic Science Learning Center. (2015). Huntington’s Disease. University of Utah Health Sciences. Retrieved from http://learn.genetics.utah.edu/content/disorders/singlegene/hunt/.

Huntington Society. (2013) What Is Huntington Disease? Huntington Society of Canada. Retrieved from http://www.huntingtonsociety.ca/learn-about-hd/what-is-huntingtons/.

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