Huntington’s disease is an incurable, hereditary brain disorder. It is a disastrous disease that causes damage to brain cells, or neurons.
HD occurs when a faulty gene causes toxic proteins to gather in the brain. Huntington’s disease (HD) affects one person in every 10,000, or around 30,000 people in the United States.
Another 150,000 or more people are at risk of establishing the condition.
The first signs usually appear between the ages of 30 and 50 years.
Huntington’s disease (HD) is a neurological condition. Huntington’s disease (HD) is an inherited disease that damages nerve cells often over time.
Toxic proteins collect in the brain and cause damage, which advances to neurological symptoms.
With deterioration from parts of the brain, this affects the movement, behavior, and cognition. It will be harder to walk, think, reason, swallow, and talk. Soon, people with HD will need full-time care, and complications are commonly fatal.
There is yet no cure for HD but treatment can help with symptoms.
According to the Huntington’s Disease Society of America (HDSA), the symptoms of HD can feel like having amyotrophic lateral sclerosis (ALS), Parkinson’s and Alzheimer’s all in one.
Symptoms of HD include:
- depression, mood swings and personality changes
- issues with memory and judgment
- trouble walking and uncontrollable movements
- difficulty speaking and swallowing, and weight loss
How signs and symptoms enhance can vary between individuals. In some cases, depression begins before motor skills are affected. Mood swings and unusual behavior are commonly the earlier signs.
Initial signs and symptoms include:
- slight uncontrollable movements
- little changes in coordination and clumsiness
- slight signs of mood and emotional change
- lack of focus, slight concentration problems, and difficulty functioning, (difficulty at work)
- lapses in short-term memory
Other possible signs of HD may include stumbling, dropping things, and forgetting people’s names. However, most people do these from time to time.
In time, symptoms become more severe.
These include physical changes, decrease of motion control, and emotional and cognitive changes.
Physical changes include:
- difficulty speaking, including looking for words and slurring
- weight loss, leading to weakness
- difficulty eating and swallowing, as the muscles in the mouth and diaphragm may not work properly
- risk of choking, especially in the later stages
There may be uncontrollable body movements, including:
- uncontrollable movements of the face
- jerking of parts of the face and the head
- flicking or fidgety movements of the arms, legs, and body
- lurching and stumbling
As HD grows, the uncontrollable movements occur more often and usually becomes more intense and the person will be slower as the muscles becomes more stern.
These may alternate rather than occurring consistently.
- antisocial behavior
- lack of emotion becomes more apparent
- cognitive changes
HD late stages:
Eventually, the person will no longer be able to walk or talk, and they will need full nursing care.
However, they do comprehend most of what is being said and have knowledge of their surroundings.
HD is caused by a faulty gene (mhTT) on chromosome number 4.
A ordinary copy of the gene produces huntingtin, a protein. The faulty gene is bigger usual. This extends to excessive production of cytosine, adenine, and guanine (CAG), the building blocks of DNA. Normally, CAG repeats between 10 and 35 times, but in HD, it repeats from 36 to 120 times. If it repeats 40 times or more, symptoms are likely to occur.
These changes results in a larger form of huntingtin. This is toxic, and, as it compiles in the brain, and causes damage to the brain cells.
Certain brain cells are sensitive to the larger form of huntingtin, mostly those related to movement, thinking, and memory. It cripple their function and eventually damaging them. Scientists do not know how this develops.
How is it inherited?
HD is familiar as an autosomal dominant disorder. This means that only one copy of the faulty gene, inherited from either the mother or the father, is necessary to produce the disease.
A person with the gene has one good copy of the gene and one faulty copy of the gene. Any offspring will inherit either the good copy or the faulty one. The child who inherits the good copy will not develop HD. The child who inherits a faulty copy will.
HD can affect several generations.
The symptoms are different, and can include leg stiffness, tremors, and regression in learning.
There is no treatment that can reverse or slow down the affects.
However, some symptoms can be managed with medication and therapies.
Anyone who has a diagnosis of depression, especially with suicidal thoughts, should not use tretrabenazine.
Drugs to control movements, outbursts, and hallucinations may include:
- clonazepam (Klonopin)
- clozapine (Clorazil)
Scientists are hopful that gene therapy will find a solution to the disease. Researchers have been looking for ways to use gene therapy for cure, slow, or prevent HD.
One strategy is to use molecules known as synthetic small interfering RNAs (siRNAs) to suppress protein production from the faulty gene.
This would stop the toxic Huntingtin protein from collecting and causing symptoms.
Here are some references:
Simon C Warby, Rona K Graham, and Michael R Hayden. Huntington Disease. GeneReviews. December 11, 2014; http://www.ncbi.nlm.nih.gov/books/NBK1305/.
Huntington disease. Genetics Home Reference. June, 2013; http://ghr.nlm.nih.gov/condition/huntington-disease.
Huntington disease. MedlinePlus. May 28, 2013; http://www.nlm.nih.gov/medlineplus/ency/article/000770.htm.
Idan Sharon. Huntington Disease Dementia. Medscape Reference. April 18, 2014; http://emedicine.medscape.com/article/289706-overview.
Fredy J Revilla. Huntington Disease. Medscape Reference. July 9, 2015; http://emedicine.medscape.com/article/1150165-overview.