Huntington Disease (HD) is a degenerative brain disorder that isinherited. One of the earlier names for Huntington Disease waschoreography, the Greek word for dance. The word chorea describes howpeople with this disorder would twist, turn constantly and theiruncontrollable dance-like motions. A lot of other names have been known inthe past for Huntington Disease also. In 1872 George Huntington, anAmerican physician wrote about this disease saying, “an heirloom fromgenerations away back in the dim past.” Later Huntington Disease was namedafter George Huntington.
The signs of HD are usually very gradual. They can go unnoticed foryears. The symptoms vary according to the size of the expansion of the HDgene, the larger the HD gene the earlier in life symptoms begin to show.The signs and symptoms vary from person to person, in one person symptomscould be higher in one area and lower in another. Symptoms includemovement disorder, cognitive disorder and psychiatric disorder. Movementdisorder includes things like fidgetiness or a nervous restlessness thatevolve to abnormal movements that are hard to control. Cognitive disordercauses difficulty in mental flexibility; it makes it hard for the person toswitch tasks quickly. It also could make it hard for them to learn newinformation.
The psychiatric disorder in HD includes depression, anxiety,obsessive ness, irritability, social withdrawal, impulsiveness, and troubleinitiating activity. In some cases it could include aggressive outburst orhallucinations.HD is an inherited disease. The impact of the gene depends onwhether it is dominate or recessive. If the gene is dominate then only oneof the paired chromosomes is required for the effect.
If the gene isrecessive then both parents must provide chromosomal copies for the traitto be present. HD is an autosomal chromosome. In individuals with HD, onegene of this gene pair (the HD gene) is not functioning correctly anddominates the other working gene. Since it is not on one of the sexchromosomes, it can affect both males and females. Males and females havethe same chance of having affected children. Each child with a defectedparent has a 50% chance of having Hunting disease.
However, withincreasing age and no symptoms the likelihood of getting the diseasedecreases to less than 50%. The gene for Huntington Disease is found on thefourth chromosome. Part of the sequence of nucleotides is CAG (cytosine,adenine, and guanine); normally the sequence is duplicated up to 26 timesin an individual. In HD trinucleotide repeat occurs which is when thesequence CAG is repeated over and over again. People with HuntingtonDisease may have the sequence repeated anywhere from 40 to over 100 times.
The effects of HD on humans can include things like the individualexperiences mood swings or becomes uncharacteristically irritable,apathetic, passive, depressed, or angry. HD can affect the individual’sjudgment, memory, and other cognitive functions. Early signs could behaving trouble driving, having a hard time learning new things, rememberingthings, problems answering questions, or troubles making a decision. Somemay even display changes in handwriting.
As the disease progresses,concentration on intellectual tasks becomes increasingly difficult.Treatment for HD can be divided into two categories: the ones fortreating symptoms of the disease and the ones that slow down theprogression of the disease. There are currently no treatments for thedisease but there are clinical trials in process aiming in the twocategories. Medications can be prescribed but must be used with caution.It can cause severe side affects for people and medication changesdepending on what stage of the disease they are in, so it should be checkedoften.In conclusion Huntington Disease has many different symptoms, andmany effects on humans.
It is located on the fourth chromosome and is onan autosomal chromosome. HD has no current treatments but medications canbe prescribed to help with the affects of HD and research is still going totry and find treatments for HD.