Introduction
By any standards, the Huntington’s chorea disease, also known as the Huntington Disorder (HD), is one of the worst neurodegenerative genetic disorders of the 21st century. Other irreversible dementias in its league include Alzheimer’s disease, vascular dementia, Parkinson’s disease, Frontotemporal dementia, and Creutzfeldt-Jacobson disease (Rabins, 2009). The word ‘chorea’ is a Greek terminology that literally means to ‘dance,’ in reference to the fidgety and uncoordinated movements demonstrated by victims of this disease. Huntington’s chorea disease, thereafter, referred as HD, is named after George Huntington, a health professional from Ohio, U.S., who first reported the strange ailment in 1872 after observing some peculiar characteristics in a family on Long Island, New York (Cattaneo et al, 2002). Today, medical professionals agree that HD is one of the most widespread genetic and hereditary diseases of the brain, affecting approximately one individual in every 10,000 (Cattaneo et al, 2000). This paper aims to critically evaluate the disorder.
Definition and Diagnosis
HD is a neurodegenerative heritable disease of the central nervous system that is characterized by anomalies in muscle coordination, cognitive mutilation, and other psychiatric manifestations, eventually leading to uncontrollable body movements and dementia (Rabins, 2009; Bernhardt et al, 2009). This disorder usually affects people who posses the predisposed HD gene, especially during their prime years of life (Cattaneo et al, 2002). This, however, does not mean that the disorder cannot present itself during other phases of life such as childhood or adolescence. To the contrary, the disease largely depends on a multiplicity of factors, and can strike at any given time according to the family’s predisposition to the causative gene (Bernhardt et al, 2009).
The medical diagnosis of this disorder can be initiated after the manifestation of physical symptoms, which are fundamentally specific to HD such as uncontrollable movements and general restlessness. In the event that there exists no family history of the disorder, individuals have an alternative of using genetic testing such as predictive DNA testing to corroborate the physical symptoms witnessed (Bernhardt et al, 2009). According to the group of researchers, “…direct DNA testing has become feasible [since 1993] providing definitive evaluations and thus more reliable results than indirect testing” (p. 295). Individuals are always encouraged to undergo genetic testing even before the commencement of the physical symptoms since the procedure has the capacity to substantiate if a person carries the predisposed gene known as the HTT gene, and which is inarguably responsible for the disease (Quarrel, 2008). Genetic counseling must be availed to individuals willing to undergo the testing procedure due to obvious ramifications involved. Individuals planning to have their babies through in vitro fertilization can decide for the embryos to be tested for the HD disorder using a procedure known as pre-implantation genetic disorder.
Facts
HD has several distinct facts that distinguish it from other genetic disorders. First, it is a well-known fact that HD is a mental disorder that is readily inherited in a family setting (HCMC, 2009). It has been well documented that the disorder is more prevalent in populations of Western European descent. The disease, however, is less prevalent in Asia and Africa (Quarrel, 2008). The disease is estimated to affect approximately one individual in every 10,000, with the estimates considerably biased according to geographical localities and family linkages (Cattaneo et al, 2002). It is a well-known fact that although HD principally affects the brain and the central nervous system, most individuals afflicted by the disorder ultimately die from heart or respiratory-related complications. It is also within the realms of our understanding that the first symptoms of the disorder often occur between the ages of thirty-five and forty years. The onset, however, can come as early as the age of 2 or delay until the individual is in his or her 70s, depending on heredity influences (Cattaneo et al, 2002; HCMC, 2009).
To continue on the facts about the disease, it is well known that the initial concise description was offered in 1872 by physician George Huntington. According to Quarrel (2008), “…it is difficult to date the onset of problems precisely, but in general the condition lasts for about 20 years” (p. 1). Another fact is that, although the disorder is viewed as rare within the medical circles, its genetic nature inarguably means that the disease affects a huge number of family members. The fact that no other animals have ever been affected by HD apart from humans is indeed mysterious. HD affects both sexes equally, but symptoms can vary from person to person, family relations notwithstanding (HCMC, 2009). It is also well known that children who develop the juvenile type of the disorder die before reaching adulthood. What’s more, it is well documented that the disorder is caused by a dominant gene, and that a child of an individual with HD has a 50 percent probability of inheriting the predisposed gene. Lastly, there is no effective treatment or known cure for the disorder.
Genetics
HD is believed to be caused by an impairment of the Huntington disease gene. The impairment triggers dominant mutation or alteration of either of the victim’s two copies of the Huntington gene, implying that each child of an individual living with the disorder has a 50 percent probability of inheriting the disease-causing gene (Quarrel, 2008). In rare occurrences where both parents have the disease-causing gene, or in other circumstances where one parent has two impaired copies of the gene, the risk of parent-child transmission is greatly increased. A child, however, cannot in any way develop HD if he or she didn’t inherent the gene in question (MedTV, 2010).
Scientists argue that the HD gene is responsible for availing genetic information and construction of a protein called huntingtin. To date, the functions of this protein remain largely anonymous, but it is thought to play a significant task in nerve cells (MedTV, 2010). When impairment occurs within the HD gene, the body system reacts by forming an anomalous huntingtin protein. The anomalous protein, according to scientists, disturbs the usual functioning of nerve cells, inexorably causing their untimely death. It is believed that the ultimate dysfunction and death of nerve cells cause the physical signs and symptoms of HD. As such, it is only safe to argue that the disorder originates from a dominant gene, which after impairment, causes some important brain cells to worsen (Quarrel, 2008). Consequently, every person who carries the HD gene will certainly develop the disorder during the lifespan unless they die of other natural or artificial causes before developing the symptoms of HD (HCMC, 2009).
Symptoms of HD
The documented signs and symptoms of HD are many and wide-ranging and differ from one individual to the other even in cases where such individuals may be related. The physical indicators of the disorder can begin at any given age within an individual’s lifespan, but mostly begin between the prime ages of 35 and 45 years (Rabins, 2009). Symptoms of HD, however, progress much quicker and differ slightly in the event that they occur before the victim reaches the age of 20 years. Some symptoms of HD related to movement and coordination include clumsiness; loss of balance; recurring, asymmetrical movement of eyebrows; uncontrolled jerking movements including unbalanced coordination of limbs and trunk; facial grimaces; inflexible muscles; difficulties in walking; and halting speech (RelayHealth, 2009).
Some symptoms of the disorder that are directly related to personality, cognitive, and mental functioning include: hallucinations; delusions; negligence of personal form and hygiene; development of a suspicious attitude without cause; neglecting personal and official duties, including work; high incidences of depression; easily irritable; irresponsible and violent behavior; loss of memory; impulsive behavior; loss of logical thinking; inability to exercise judgment; and becoming increasingly unaware of other people, place, and time-periods (RelayHealth, 2009).
Prognosis
Presently, there exists no probability of recovering from HD once it sets in. The disorder is known to progress without lessening over a span of between 10 and 20 years. The pathology of HD is not critical, but the complications and impediments arising from the disorder’s symptoms become progressively more dangerous. This is largely supported by the notion that although HD is a disease of the brain, most individuals’ end up dying of respiratory infections such as pneumonia, and a host of other factors, including accidental choking, suicide, and heart failure (Kennard, 2006).
Treatment
As already mentioned, there exists no cure for the disorder. Health professionals, however, have formulated treatment processes that aim to minimize some of the symptoms exhibited by victims of HD. For instance, some drugs can be administered to assist in minimizing the fidgety movements, while others somewhat assist to control the victim’s behavior (RelayHealth, 2009). It is prudent for HD victims to contact a physical therapist (PT) or an occupational therapist (OT) so that they may be assisted to get the therapeutic services to help them stay physically independent. A qualified PT or OT has the capacity to assist the victim identify and work through postural and balance dysfunctions if help is sought early enough (Quarrel, 2008).
These PT and OT professionals comes in handy to assist victims of HD surmount walking and coordination difficulties through engaging them in goal-directed exercises, which may be offered through a home-based program (Quarrel, 2008). Therapists are also better placed to provide the victim with proper adaptive equipment, teach efficient compensatory approaches, and help in the establishment of a safe home environment to keep self-inflicted injuries at bay. This can be achieved through scheduled home visits. In the later stages of disease progression, the therapists are also needed to assist the victims with daily living and stress management skills. A disappointing reality, though, is that there is no cure for the disorder.
Reference List
Bernhardt, C., Schwan, A.M., Kraus, P., Epplen, J.T., & Kunstmann, E. (2009). Decreasing uptake of predictive testing for Huntington’s disease in a German Center: 12 years experience (1993-2004). European Journal of Human Genetics, Vol. 17, Issue 3, p. 295-300.
Cattaneo, E., Rigamonti, D., & Zuccato, C. (2002). The enigma of Huntington’s disease. Scientific American, Vol. 287, Issue 6.
Hennepin County Medical Center. (2009). Facts about Huntington’s disease. Web.
Kennard, C. (2006). Huntington’s disease. Web.
MedTV. (2010). Genetics of Huntington’s disease. Web.
Quarrel, O. (2008). Huntington’s disease: The Facts, 2nd Ed. New York: Oxford University Press.
Rabins, P.V. (2009). Irreversible Dementias. Memory, p. 29-34. Web.
RelayHealth. (2009). Huntington’s disease (HD). CRS-Adult Health Advisor, Vol. 23, Issue 2, p. 1. Web.