Huntington's disease

Huntington’s disease is a hereditary neurological disorder of the central nervous system that causes progressive degeneration of cells in the brain, slowly impairing a person's ability to walk, think, talk and reason.

• Huntington’s Disease is also called Huntington’s Chorea.  Chorea means dance which refers to the jerky symptoms of patients with the disease.
• Huntington’s Disease was first discovered by Dr. George Huntington.  The disease is named after him.

How do you get Huntington’s Disease?

Huntington's disease is caused by a genetic defect on chromosome 4. The defect causes a part of DNA, called a CAG repeat, to occur many more times than it is supposed to. Normally, this section of DNA is repeated 10 to 28 times. But in persons with Huntington's disease, it is repeated 36 to 120 times. Scientists are not sure how this works, but the extra copies cause the accumulation of toxic protein in your brain.  The more copies you have, the sooner you will get Huntington’s Disease and the more severe your symptoms will be.    

As the gene is passed down through families, the number of repeats tend to get larger. The larger the number of repeats, the greater your chance of developing symptoms at an earlier age. Therefore, as the disease is passed along in families, symptoms develop at younger and younger ages.

The tragedy is that by the time symptoms appear, the person has often had a family and may have passed on the gene to their children. Each person whose parent has Huntington's disease has a 50 per cent chance of inheriting the gene, and everyone who inherits the gene will at some stage develop the disease.

The disease can't be prevented from developing if someone has the faulty gene. To inherit the illness, the gene only has to come from one parent, making it autosomal dominant.

The gene for Huntington's disease can be detected with a blood test that can determine whether someone has the faulty gene and help them in their family planning.

Is there a cure for Huntington’s Disease?

No there is not a cure for Huntington’s Disease.  There is not even a treatment that will help slow the progression of the disease down.  However, there is medicine that will make the patient more comfortable, that will help reduce the symptoms. It’s important for people with Huntington’s Disease to stay in shape.  This helps reduce jerky movement and, like most things, people who exercise tend to do better than those who don’t.  Physical Therapy is very important as well as speech therapy to help the patient lead a more normal life. Huntington’s Disease patients need assistance performing the simplest of tasks.  That is why 24-hour care is eventually needed. Since the risk of getting Huntington’s Disease is so high if one of your parents has the gene, most people who know they have the gene chose to adopt so that their children won’t inherit the disease.

Symptoms

There is a long list of symptoms for Huntington’s Disease.  The disease causes behavioral changes such as irritability, moodiness, and antisocial behaviors.  It causes restlessness, fidgeting, paranoia, and hallucinations.  People with Huntington’s Disease lose their memory and their judgement.  They experience personality changes, confusion, disorientation, anxiety, stress, and tension.  They also lose their ability to speak.  

    

Huntington’s disease also effects people’s motor skills.  They walk unsteadily and suffer from quick and sudden jerking movements of their limbs.  They also have difficulty swallowing. If a child suffers from Huntington’s Disease symptoms they will have slow movements, tremors, and rigidity.   Overall, people with Huntington’s Disease lose the ability to care for themselves and to interact with others.  They have the potential to injure themselves of others and they have increased risk of infections.  Many people who suffer from Huntington’s Disease also suffer from depression.  A lot of Huntington’s Disease patients’deaths’ are caused by suicide and not the actual disease. Huntington’s Disease is a horrible condition that makes day to day life impossible.  Within 15 to 20 years after you see symptoms, this disorder becomes fatal.

Ethical issues

There are ethical concerns related to prenatal genetic testing or preimplantation genetic diagnosis to ensure a child is not born with a given disease. For example, prenatal testing raises the issue of selective abortion, a choice considered unacceptable by some. Using preimplantation testing for HD requires twice as many embryos to be used for in vitro fertilization, as half of them will be positive for HD. As it is a dominant disease, there are difficulties in situations in which a parent does not want to know his or her own diagnosis. This would require parts of the process to be kept secret from the parent.