Home > Disease > DNA and Huntington's Disease

DNA and Huntington's Disease

By: Ian Murnaghan BSc (hons), MSc - Updated: 3 May 2013 | comments*Discuss
 
Dna Huntington's Disease Genetic

DNA discovery has allowed researchers to identify the genetic basis for many diseases. In doing so, the path has been paved for new treatments and enhanced knowledge for preventing disease. In the case of Huntington's disease, DNA plays an important role in our understanding of how the disease occurs and hopefully one day, how it can successfully be treated.

What is Huntington's Disease?

Huntington's disease is a genetic disease that affects the central nervous system. It is unusual in comparison with many other disorders in that the symptoms typically show in adults aged 30 to 40 years, although they can be evident earlier or later than this age range. Symptoms generally include involuntary movements and a loss of motor control. A person with Huntington's disease may also suffer from personality changes, memory loss and a compromised mental capacity.

DNA and its Relationship to Huntington's Disease

Huntington's disease is an autosomal dominant disorder, which means that the gene is an autosomal chromosome as opposed to one of the sex chromosomes. If you think about the human body, we each have forty-six chromosomes that come in pairs - one from each parent. The first twenty-two pairs are autosomal chromosomes and the twenty-third pair consists of sex chromosomes. Since Huntington's disease is autosomal dominant, it means that the gene implicated in the disease is on one of the autosomal chromosomes rather than the sex chromosomes. It has been found that the fourth autosomal chromosome is involved in the disease. Those who are affected have one gene in the gene pair that is not functioning properly, which then causes it to express itself to a greater degree and thus dominates the properly functioning gene.

Those who are familiar with the basics of DNA will recall that a chromosome contains DNA, which then contains genes. Within the structure of DNA, there are nucleotides composed of a sugar, phosphate and base. In Huntington's disease, there is a DNA sequence of CAG that can be duplicated many times over, in what is known as a trinucleotide repeat. The CAG refers to the DNA bases cytosine, adenine and guanine. While the general population might have the CAG duplicated up to twenty-six times, those with Huntington's disease have it repeated from forty to more than a hundred times.

Recent Research into DNA and Huntington's Disease

One of the questions that researchers have regarding Huntington's disease involves its late onset in life. A recent theory is that the CAG segment expands over time in cells that do not divide, such as nerve cells. Thus, the disease then progresses as time passes and symptoms present themselves when a person is in his or her 30s or 40s - perhaps a bit earlier or later.

For those of us without Huntington's disease, we are normally susceptible to oxidative lesions, which are by-products of inhaled oxygen but we have DNA repair enzymes that work to keep these oxidative lesions in check. In a person with Huntington's disease, the body's cells try to remove the oxidative lesions, which are thought to cause the CAG segment to expand. DNA repair enzymes still exist in those with Huntington's disease as with the general population, but these repair systems can become overwhelmed by the oxidative lesions as time goes on. It is likely that this expansion of the CAG segment and reduced capacity of the DNA repair system to handle oxidative lesions leads to the late onset of symptoms. The link between oxidative lesions and Huntington's disease has been confirmed with laboratory experiments on mice. Scientists are hopeful that new treatments that address these oxidative legions can prevent the onset of the disease. They are also optimistic that the research might be helpful for other diseases where oxidative lesions are thought to play a role, such as Alzheimer's disease.

You might also like...
Share Your Story, Join the Discussion or Seek Advice..
Why not be the first to leave a comment for discussion, ask for advice or share your story...

If you'd like to ask a question one of our experts (workload permitting) or a helpful reader hopefully can help you... We also love comments and interesting stories

Title:
(never shown)
Firstname:
(never shown)
Surname:
(never shown)
Email:
(never shown)
Nickname:
(shown)
Comment:
Validate:
Enter word:
Topics
Latest Comments
  • Rebekka
    Re: DNA and Air Crash Victims
    How does one obtain dna for ancestral testing from a body that's been embalmed? They are holding the body while I find out. Can you…
    26 April 2019
  • Nikita
    Re: DNA Test after Death
    Hello, I just saw your tests online. Great!! I am wondering my mother died about 20 years ago. I have 1/2 of her ashes. I am trying to find…
    29 March 2019
  • Morgz
    Re: An Overview of DNA Functions
    GO CHECK OUT MY NEW CLICKBAIT FORTNITE CHANNEL!!! MORGZCLICKBAITY
    26 March 2019
  • Shegzysnoop
    Re: Using DNA and for Immigration Purposes
    My dna is part of the document that was receive by the consulate from my lawyer in Chicago but surprisingly afelter…
    20 March 2019
  • yoda gaming
    Re: An Overview of DNA Functions
    game i must 3 weeks left to live i have took the kids she has
    19 March 2019
  • Lannette
    Re: DNA Test after Death
    My son was killed n 2018 and was buried can or shall I say could we get a good enough DNA to see if a child who's going on 10 next month…
    14 March 2019
  • Emilina C.
    Re: DNA Test after Death
    My uncle died in March 2017 and there is a probable theory that he was murdered by his wife due to the fact that his reason for being sent to…
    14 March 2019
  • lora
    Re: Using DNA and for Immigration Purposes
    my husband is petioning me, we went our different ways but we werent divorced , i had my son while i was married but…
    14 March 2019
  • Jem
    Re: DNA and Disease Prediction
    Nice work it really helped me with the big project I'm doing in May.
    11 March 2019
  • Brat
    Re: DNA Test after Death
    My daughters father just died yesterday he hasn't been buried or cremated is there any way that we could still do a DNA test to prove he is…
    9 March 2019