Huntington’s Disease

After examining the effects of the disorder, it is easy to understand what a disease like Huntington’s will to do to an individual’s quality of life. Imagine being 30 years old with a good job, a loving spouse, maybe a

couple of kids and an all around pretty good life. Then imagine one day your boss writes you up and sends you home because he/she suspects you of being intoxicated. A person in this situation could, in months and years to come, learn from a simple blood test that he/she is the victim of a genetic disorder called Huntington’s Disease. The ramifications of this illness are endless and affect not only the individual with the disorder but entire families and communities as well. At this time there is no cure or even any significantly effective treatment (Society 2006). However, as with many genetic disorders, research is being done in this day in age that may promise to one day lead us to such treatment or cure.

Huntington’s Disease (hereafter called HD) is a degenerative brain disorder that was named in 1872 after Dr. George Huntington who first illustrated its effects. It is estimated that ¼ million people either have the disease or will develop it in their lifetime. In other words, 1 in 10,000 people will be afflicted. It has been documented to affect as many people worldwide as Hemophilia, Cystic Fibrosis or Muscular Dystrophy (Society 2006). The HD gene is inherited in an autosomal dominant fashion which means that any person who receives the mutated gene will eventually have the disorder. This also means that males and females have an equal chance of inheriting the gene. Also, the gene does not stop at any racial or ethnic boundaries so people are at risk worldwide. The short arm of human chromosome #4 is where the HD gene has been mapped to. It was located in 1993 and offers a definitive test to determine if someone is at risk. The actual mutation is a trinucleotide repeat of CAG (Cytosine, Adenine, Guanine). The greater the number of repeats, the more severe the disease. In a normal person, there are 35 or fewer CAG repeats. People with 36-39 may or may not be afflicted. Those with 40 or more repeats will almost certainly develop HD (Society 2006).

Because HD is a degenerative disease, the effects show up gradually within a person’s phenotype. Since many areas of the brain can be affected, the early symptoms can vary from person to person, and they range from cognitive to motor function to emotional difficulties. Family members or friends may first notice an affected individual exhibiting depression, mood swings, forgetfulness, clumsiness, involuntary twitching and social withdrawal. As the disease progresses, one might lose his capacity to concentrate and remember things in the short term. Extreme irritability, loss of organization, slurred speech and problems with swallowing and walking are also severe symptoms of HD. Eventually, a person with the disease will need constant care (Society 2006).

The age of onset is pretty standard for HD. Most individuals first exhibit signs between 30 and 45 years of age. Generally people live 10 to 25 years after learning they are affected. Because of the effects of HD, most people don’t die specifically from the disease but rather from choking, pneumonia or heart failure once they are severely incapacitated. Since there is not yet any form of treatment, early diagnosis would not make a difference for those with HD. In fact, some people who know they may be at risk elect not to be tested (Society 2006).

Although the outlook for people today with HD may look grim, significant research into treatments is underway. Some modes of therapy available today are botox injections used to calm involuntary twitching in facial muscles as well as occupational and physical therapy to offset motor function problems and speech therapy for those who find it hard to communicate (Society 2006). As far as pending research is concerned, the Huntington’s disease Society of America (HDSA) is one of the leading groups who are pioneering new ways to look at the genomic and molecular levels of HD. Some areas of their research include examination of: 1) the energy needed in the cell mitochondria of HD patients, 2) the folding of the huntingtin protein (the protein expressed by the area of chromosome 4 linked to the disease) and how it makes the cell unable to dispose of the mutated strain, and 3) the way huntingtin works in normal people versus the affected with the mutated huntingtin protein (Society 2006). A fairly recent and exciting discovery of doctors associated with HDSA suggests a correlation between degenerative diseases like Huntington’s and cancer. Although they might seem very different at first glance because cancer is characterized by cells that divide too rapidly while HD causes neurons (which aren’t designed to divide) to die, new research shows that the same signal that causes these cancer cells to divide may make brain cells degrade (Marker 2005). Yet another possible similarity between cancer and HD involves p53, a tumor suppressor that is created by the body which regulates cell division. In a person with cancer, this tumor suppressor is mutated and allows cells to divide uncontrollably. Some scientists believe that the mutated huntingtin protein could actually over activate p53 and cause brain cells in affected people to slowly die (Marker 2005). The last piece of research to be discussed here are the recent findings of Dr. Robert Friedlander. He found that a certain enzyme created in the body called caspase-1 which kills off mutated cells in a normal human being may be over activated in HD patients causing the enzyme to kill healthy brain cells (Association 2006). Dr. Friedlander found that he could diminish the function of caspase-1with an antibiotic called Minocycline, and in turn he could delay the onset and the progression of the effects of HD in mice (Chen 2000).

As one can see, Huntington’s is a truly debilitating and emotionally straining disease. It affects people across the globe in every portion of their daily life. Not unlike many diseases today such as Parkinson’s, afflicted people become 100% dependent on loved ones or medical professionals for activities of daily living once they have progressed to the final stages of HD. We can only hope that some of the research outlined in this paper, or possibly scientific breakthroughs to come, might one day lead to successful treatment.