Disorder Specialist - Your role as the disorder specialist is to karyotype the disorder, find out all of the signs and symptoms of the disorder, including a detailed description of how it affects the human body. Also, find out what different tests could have been provided to the parent to have found out about this disorder before its birth.

http://www.nlm.nih.gov/medlineplus/ency/article/000770.htm
http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=huntington
http://ghr.nlm.nih.gov/condition=huntingtondisease



Karyotype:

karyotype.gif

Karyotype for Huntington's Disease
http://www.nkellogg.com/karyotype.gif

The chromosome number 4 is affected by this disease.



Causes:
Huntington's disease is caused by a genetic defect on chromosome #4. The defect causes a part of DNA, called a CAG repeat, to occur many more times than it is supposed to. Normally, this section of DNA is repeated 10 to 35 times. But in persons with Huntington's disease, it is repeated 36 to 120 times.

The huntingtin gene on chromosome 4.


Discouragement
As the gene is passed on from one generation to the next, the number of repeats - called a CAG repeat expansion - tend to get larger. The larger the number of repeats, the greater your chance of developing symptoms at an earlier age.
If one of your parents has Huntington's disease, you have a 50% chance of getting the gene for the disease. If you get the gene from your parents, you will develop the disease at some point in your life, and can pass it onto your children. If you do not get the gene from your parents, you cannot pass the gene onto your children.



Signs and Symptoms:

http://www.neurologychannel.com/huntingtons/symptoms.shtml

Early symptoms of this disease vary from person to person. The earlier the symptoms appear, the faster the disease progresses.

Family members may first notice that the individual experiences mood swings or becomes uncharacteristically irritable, apathetic, passive, depressed, or angry. These symptoms may lessen as the disease progresses or, in some individuals, may continue and include hostile outbursts or deep bouts of depression.

There are three different categories for the symptoms for Huntington's disease:
Movement, Cognitive and Psychiatric.

Further Info:

Movement:
Uncontrolled movement, or tics, may develop in the fingers, feet, face, or trunk. This is the beginning stage of chorea—involuntary, rapid, ceaseless movement. Chorea can become more intense when the person is anxious or disturbed. Over time other symptoms, such as the following, emerge:
  • Clumsiness
  • Jaw clenching (bruxism)
  • Loss of coordination and balance
  • Slurred speech
  • Swallowing and/or eating difficulty
  • Uncontrolled continual muscular contractions, also known as dystonia
  • Walking difficulty, stumbling, falling

Cognitive:
Over time judgment, memory, and other cognitive functions begin to deteriorate into dementia. As Huntington's disease progresses, the ability to concentrate becomes more difficult. The person may have difficulty driving, keeping track of things, making decisions, answering questions, and may lose the ability to recognize familiar objects.

Psychiatric:
Early psychiatric symptoms of Huntington's disease are subtle, varied, and easily overlooked or misinterpreted. Depression is the most common psychiatric symptom of Huntington's and often develops early in the course of the disease. Signs of depression include:
  • Hostility/irritability
  • Inability to take pleasure in life (anhedonia)
  • Lack of energy
Some people develop manic-depression, or bipolar disorder, during the course of the disease.
A person with Huntington's also may exhibit psychotic behavior:
  • Delusions
  • Hallucinations
  • Inappropriate behavior (e.g., unprovoked aggression)
  • Paranoia



Abnormal and unusual movements
  • Head turning to shift eye position
  • Facial movements, including grimaces
  • Slow, uncontrolled movements
  • Quick, sudden, jerking movements of arms, legs, face, and other body parts
  • Unsteady gait
  • Behavior changes
    • Antisocial behaviors
    • Hallucinations
    • Irritability
    • Moodiness
    • Restlessness or fidgeting
    • Paranoia
    • Psychosis
  • Dementia that slowly gets worse, including
    • Loss of memory
    • Loss of judgment
    • Speech changes
    • Personality changes
    • Disorientation or confusion



    • disturbance
    • torpor/stupor
    • slower thinking
    • narrowing of range of interest

    • change of personality
    • depression
    • obsession
    • delusion+
    • hallucination
    • sometimes psychosis

In late-onset disease (after age 50), the patient may suffer depression rather than experience sudden anger or irritability, and their memory, reasoning, and problem-solving skills may remain sharp.
Early signs of juvenile Huntington's disease often include subtle changes in handwriting and a rapid decline in school performance. The child may develop seemingly minor movement disorders, such as slowness, rigidity, tremor, or rapid muscle twitching. Other early signs of disease may include these changes:
    • Behavioral changes

    • Difficulty learning new things

    • Speech difficulties
Children under the age of 15 may experience recurrent seizures and akinesia—muscle rigidity and stiffness. Children from 15 to 18 years of age tend to manifest the same symptoms of Huntington's disease as adults.


http://www.ygyh.org/hd/diagnosis.htm

http://www.rbhs208.org/sterling/genetic%20disorder.htm