Huntington’s Part One!

Although I realize the ridiculousness of my first blog post after school has officially started it really has been a busy summer! In this post I’m going to give a summary of all the different aspects of Huntington’s. In my second post I will look at the ethical issues associated with the testing for Huntington’s and it’s path of inheritance and in my third I will talk about various new drug trials, treatments and the research currently going on.
What really stunned me most about my research this summer was the pure magnitude of the information known about Huntington’s. I expected it to still be a rather mysterious disease since there seems to be such confusion surrounding how best to treat it. Although lots is known about the disease there are several key problems with truly identifying the root of the disease.
Huntington’s is caused by a genetic defect on chromosome four. A section of the DNA strand is repeated more often than it should be. As the gene is passed on the number of repeats on the strand tends to grow longer which means the symptoms of Huntington’s begin to appear at younger and younger ages. If one of your parents has Huntington’s you have a 50% chance of inheriting the gene. The exact function of the huntingtin protein is unknown but it seems to play a role in nerve cells. The defect on chromosome 4 causes the protein to become malformed and become prone to clumping in the brain, which leads to the death of many nerve cells. The mutant protein accumulates abnormally throughout the entire body but only kills cells in the corpus striatum.
The most affected areas in the basal ganglia and the cortex the areas of the brain that controls movement and thoughts are the most affected areas of the brain. Within the basal ganglia Huntington’s especially targets the neurons of the striatum particularly the nerve cells of the caudate and the pallidium which are both very important parts of the brain.
All of these factors eventually manifest as behavioral and movement problems. The behavioral problems generally appear before the movement issues and can include antisocial behavior, hallucinations, moodiness, paranoia and psychosis. Movement symptoms can include head turns in order to shift eye position, facial ticks, unsteady gait, and quick or jerky movements of the arms, legs and other body parts. Patients generally die within 15 or 20 of symptoms appearing but they rarely die from the actual disease. Infection is generally the cause of death is common but suicide is also common.