Understanding Huntington's Disease Essay

Huntington’s Disease is a brain disorder affecting movement, cognition, and emotions (Schoenstadt). It is a genetic disorder generally affecting people in their middle 30s and 40s (Sheth). Worldwide, Huntington’s disease (affects between 3-7 per 100,000 people of European ancestry (Schoenstadt). In the United States alone, 1 in every 30,000 people has Huntington’s disease (Genetic Learning Center). Huntington’s Disease is a multi-faceted disease, with a complex inheritance pattern and a wide range of symptoms. There is also much research being done in the field of Huntington’s disease, because as of 2012, this disease is untreatable. THESIS.

Huntington’s disease is an autosomal, dominant inherited disorder caused by a polyglutamine expansion at the amino-terminal on the huntingtin protein. It causes a progressive degeneration of spiny nerve cells in the striatum and cortex of the brain, impairing a person’s functional and cognitive abilities. Polyglutamine repeats of 36 are found to be non-threating but sequences containing an additional two or three repeats are associated with Huntington’s disease.

Huntington’s disease can be tested for by looking at the number “CAG repeats,” on chromosome 4 (Appai-Kubi.) During pregnancy, a

Huntington’s disease would affect motor movements such as doing jerks and twitches. Tremors would spread and gradually interfere with walking, speech, and other voluntary movements.

Huntington’s disease is a hereditary brain disorder that is progressive in neurodegeneration; which means, there is a loss of function and structures of one’s neurons. In the long run it results in the loss of both mental and physical control. The disease affects muscle coordination, cognition and behavior. It used to be known as Huntington’s chorea because it is the most common genetic disease that is the cause of abnormal twitching. Huntington 's has an intense effect on patients, as individuals gradually lose the ability to reason, speak and swallow. Also, motor symptoms, which affects in problems with walking, (Mayo Clinic Staff, 2011).

Symptoms that may be expressed include memory loss, mood swings, slurred speech, depression, and death usually from heart disease or pneumonia. There can also be steady downfall of the person mental health. This also can destroy two small regions of the brain (the putamen and the caudate nucleus) that help control movement.

Huntington’s disease is a neurodegenerative disorder that is inherited in an autosomal dominant fashion. The cytoplasmic protein affected in Huntington’s disease is Huntingtin, coded for by the Huntingtin gene. The mutated version of the Huntingtin protein has several degenerative consequences on the molecular level. These are mainly caused by the elongated chain of glutamines that abberantly interacts with proteins and diminishes their biological functions. The mutated protein also tends to misfold and form aggregates in neurons, diminishing normal neural functions and producing the phenotypic traits characterized by Huntington’s disease.

Rooting back to the middle ages the now commonly known Huntington’s disease is the cause of death in one out of 15000 people around the globe. The disease’s existence is documented through history under many different names depending on the amount of information that was gathered through the unusual progression of the disease. The disease was referred to as Chorea initially due to the jerky movements of the patients affected by it. The first thorough description of the disease surfaced in 1872 as George Huntington whom the disease is named after today presented a detailed definition of the disease through his first paper. George Huntington was able to accurately detect the pattern of inheritance of an autosomal dominant disease by examining the combined medical histories of a family that clearly suffered from the disease through generations. The disease could not be studied further until the rediscovery of the Mendelian Inheritance in the 20th century that allowed scientist to look further into the autosomal dominant disease.

George Huntington was not the first to describe the disease, but he was the first to present an account in concise clear detail. After Huntington’s research, the disease was known as Huntington chorea. Chorea meaning sporadic, involuntary movements. As time has progressed, research has as well, and this disease has come to be known as Huntington’s disease (HD). Huntington’s is a neurodegenerative disorder that is autosomal dominant, meaning the defective gene needs only be inherited from one parent. The cause of HD is a defect that occurs on chromosome 4 and as mentioned above is hereditary. This disease affects the cognitive, motor and emotional functions of the brain. Oliver Quarrell put in simpler terms the actions of the brain cells in a book he wrote stating the known facts of Huntington’s disease. Quarrell (1999) described a person with this disease to have, “some nerve cells, in specific areas of the brain, die back early” (p.2). The action of cells dying prematurely leads to two forms of Huntington’s; Adult

Huntington’s Disease (HD) is a genetic disorder in which the necrosis of cells in the brain causes early death [9]. The neurodegeneration of the brain leads to mechanical and psychological symptoms, which can present normally from 30 to 50 years of age or even earlier, which is referred to as Juvenile Huntington’s Disease [3,5,6]. Some mechanical symptoms of HD are change in gait, uncontrolled or sudden movement, abnormal face movement, turning the whole head instead of using the eyes, difficulty swallowing, impairment of speech and general decrease of motor skills [1]. Psychological symptoms include but are not limited to paranoia, irritability, mood swings, changes in behavior such as agitation or instability and

About 13 years ago while at a golf course with my father, we crossed paths with an old college friend of his that he had not seen in quite some time. The middle age man approached us with what appeared to be a stuttering step and as I reached out to shake his hand, I remember noticing his arms jerk involuntarily as his hand stretched out to meet mine. He introduced himself and began reminiscing with my father. I remember being fascinated by how proper and elegant he spoke. As they parted ways, my father turned to me and before I could ask he said “my friend has Huntington disease.”

Huntington’s disease was named after George Huntington a physician in America. He was able to shed light on the diseases observable appearance and how it is inherited in a paper he wrote about the disease.

Huntington's disease is a genetic disease. It is an autosomal dominant disorder which means that a single defective gene copy will cause the disease because it inherits the defect in a single gene caused by a mutation in the HD (also known as HTT) gene on chromosome 4.

Huntington’s Disease (HD) is defined as being a progressive neurodegenerative condition which can be characterized by cognitive, motor and behavioral problems (Mestre, Ferreira, Coelho, Sampaio, & Costa, 2009). It is an autosomal dominant disease, meaning that if a child’s parent is affected by HD, there is a 50% chance the child will be affected as well. Huntington’s disease (first known as Huntington’s Chorea) was first documented and studied in 1872 by George Huntingon, MD (Aubeeluck & Wilson, 2008, p. 146; Bourne, Clayton, Murch, & Grant, 2006). Almost 150 years later there is still little known about this disease, which contains no cure in sight.

The name Huntington’s disease comes from an American physician, George Huntington (see figure 1), after he was the first person to give an official description of the disease in 1872 (Bhattacharyya, 2016). In Canada alone, more than 21 000 individuals have been affected by Huntington’s Disease, an incurable illness that results in death typically between 15-20 years after diagnosis (Scrivener, 2013). This disease causes both physical and mental changes in an individual, therefore completely changing one’s way of life.