Lab 1 Essay

Submitted By dextenor
Words: 1780
Pages: 8

Huntington’s Disease Case Study

Huntington’s disease, also called HD or Huntington's chorea, is a genetic disease that is found in many people throughout the world. Genetic diseases are different from other types of diseases, because genetic diseases start from the very beginning, birth. Parents will contain a genetic alteration somewhere in their DNA and then pass that gene on. Parents do not even need to have the disease but carry the chromosome, which contains the potential to pass it on. Huntington’s disease is one of those strange genetic diseases that can only be passed on by a parent to it’s offspring. The disease is found in the gene that produces proteins and the abnormality is called huntingtin. To truly understand Huntington’s disease these question would need to be answered, who does it affect, what are the signs, how is it cured, and are there researchers working to find new developments on Huntington’s disease. Those are the key questions in identifying all the components of Huntington’s disease (Medline Plus, 2013).

What is it?
Huntington’s disease is a genetic disease that is found on an arm in chromosome four that produces Huntingtin (Karcher, 2010). The Huntingtin defect makes part of the DNA called CAG (amino acid glutamine) reoccur excessively. The CAG section of DNA is supposed to be working at a repetition rate of ten to twenty-eight times, but when you have Huntington’s disease, those repetitions are increased greatly from thirty-six to one hundred and twenty-eight times. That is a huge difference and the higher the repetition rate the earlier the symptoms will begin to show. The excessive reoccurrence breaks down nerve cells in your brain and is eventually fatal. Most people start developing signs of Huntington’s disease in there mid thirties. When the repetition rate of CAD in the DNA is high, symptoms may begin to show signs during early childhood or in teenagers. It is much more common to see Huntington develop as adult onset rather then early onset (Medline Plus, 2013).
The genetic disease can either be dominant, recessive or X-linked. With Huntington’s disease, it is dominant. That means if the gene is present then unfortunately Huntington’s disease will be present. It also means that there is about a fifty percent chance that the mutated gene will be passed on to an offspring. The Huntingtin mutation is an insertion mutation. That means that the mutation is adding additional nucleotides in a DNA sequence. The disease will always transpire if there are more than forty repetitions of the sequence (Karcher, 2010). The disease can never be slowed down once a person has it. The dominant gene will keep allowing it to spread throughout a family’s lineage.

Populations and Symptoms
The name chorea originates from the Greek language and the word for dance because of how the disease forces your body to act. George Huntington termed Huntington’s disease chorea originally due to the symptoms his patients were showing. The patients appeared to have no control over body movements and would move occasionally at random. The huntingtin mutation is toxic to cells, which is why the neurons, specifically neurons of the striatum, start to die. Those neurons affect motor skills and movement. That is why a huge symptom of Huntington’s disease is the lack of coordination and slower movements (Karcher, 2010). The disease also targets brain function, which dictates muscle function. Other symptoms can and will develop at later stages from the desecration of neurons. One of the main disorders is the lack of cognitive skills. Dementia is a key symptom in Huntington’s disease. Dementia consists of memory problems, changes in personalities, change in speech and lack of rational thinking. Anxiety, stress, and tension are other common symptoms that can be found associated with Huntington’s disease (Medline Plus, 2013). The side affects and symptoms show just how detrimental Huntington’s is to the