Huntington’s disease: Causes, Symptoms, Treatment
Introduction
Huntington’s disease, also known as HD, is a rare degenerative disorder that greatly effects the central nervous system of the individual. It is often characterized by surplus and unwanted choreatic movements, unusual behavioral patterns, disturbances in the mental level and dementia. (Sheth 2013) As far as the Caucasian population is concerned, the Huntington’s disease is prevalent in one out of ten thousand persons. In a few cases, adolescents start to show symptoms of HD (known as JHD or Juvenile Huntington’s disease) before the age of twenty by demonstrating behavioral disorders and learning difficulties at school. However, chorea is the major indicator of the beginning of HD that spreads to all muscles with the passage of time. He/she, who affected from the disease, becomes severely retarded as the psychomotor processes are affected gradually also suffers decline of cognitive skills and starts experiencing mental disorder symptoms (Roos 2010).
If described in medical language, Huntington’s Disease is “an autosomal dominant inherited disease caused by an elongated CAG repeat (36 repeats or more) on the short arm of chromosome 4p16.3 in the Huntingtin gene” (Roos 2010). In adolescents that suffer from Juvenile Huntington’s disease, the repeat frequently goes beyond 55. The signs and clinical symptoms lay the basis for diagnosis, especially for individuals who have a parent with confirmed Huntington’s disease. The diagnosis is confirmed with the determination of DNA. Although, there is still no cure for the Huntington’s disease, the quality of life of the patients can be improved with the help of care and other available treatments. The individual with Huntington’s disease becomes completely dependent as the disease progresses and is not able to carry out even the day-to-day tasks. Death is most commonly caused by pneumonia seconded by successful suicidal attempts (Roos 2010).
The above chromosome map clearly shows there is a mutation in the Huntington’s disease.
Causes and Risks
All Huntington’s disease cases are found to be caused by the defective gene that was identified by the medical scientists in the year 1993. The huntingtin gene limitation is consisted of an added particular chemical code repeat in a minute part of chromosome 4. Normally, the huntingtin gene has a total of more or less twenty reappearances of this specific chemical code among the total codes that number three thousand around. The Huntington’s disease is caused by the chromosomal defect in which there are more than forty reappearances. For the genetic tests of the Huntington’s disease, these number of chemical codes repetitions that are present in the huntingtin protein gene of the patients are measured (Knowles 2007).
The actual function of the hungtin protein/gene is still a mystery to the scientists. They still don’t know about the process due to which dozens of surplus repeats in its genetic design cause the destructive indicators of Huntington’s disease. Any advancement and solution would be beneficial for the getting understandings of psychological disorders for instance Alzheimer’s, Parkinson’s disease etc. (Knowles 2007).
Symptoms
The symptoms of this disease may vary from person to person. There are cases when within the same family the symptoms do not match from the other family member. In some cases, emotional and behavioral symptoms are more prominent and for others, the symptoms of involuntary movements (Lemiere 2004). Following are some of the most common symptoms of Huntington’s disease.
Emotional/Behavioral Symptoms
Some of the symptoms which are usually encountered in the Huntington’s disease are anxiety, irritability, depression and apathy. Some people suffer from depression for a longer period before its recognition to be a symptom of HD. Social withdrawal, several occurrences of mood swings and impulsiveness with aggression are the behavioral changes that may show up. There are less chances of schizophrenia and other psychiatric problems in Huntington’s disease (Lemiere 2004).
Cognitive/Intellectual Symptoms
The very first signs of cognitive disturbance often are the slight changes in intellectual capacity. These signs are lack of ability to handle new situations and the organization of the routine matters as well. Long term memory stays well but short-term memory loss is a symptom too. The daily routine work/tasks become extremely difficult to perform (Lemiere 2004).
Motor Symptoms
Excessive restlessness, fidgeting, twitching are the nervous activities that are initial physical symptoms. There may be a change in the hand writing of the person. Routine activities like driving and cooking, which involve concentration and coordination, become difficult. Facial grimaces can appear as well and some involuntary movements of head and limbs. As a result, walking problem and balance maintenance can appear. During rest and taking sleep, movements decrease and the movement in stress or excitement may increase during voluntary effort (Lemiere 2004).
Being at Risk for Huntington’s disease
Huntington’s disease has different effects on different people so there is no particular condition/situation that makes a person defenseless to get affected by Huntington’s disease. Some people get so allergic of the topic that they even turn away from their family members as they do not wish to have discussions for their risk to have HD. On the other hand, there are a number of people who do nothing but constantly get afraid and think about being at risk to. (Weiner & Lipton 2003).
This is important to note here that being susceptible to Huntington’s disease is rather influential for people as it has a major effect on the choices in life including marriage, family planning and job opportunities. An occurrence of awkward situation, shuddering or absentmindedness/lack of memory may be regarded as an onset of the Huntington’s disease that may have terrifying consequences for the individual and his/her family. A good number of at-risk people show enough bravery to acknowledge the risk for Huntington’s disease. This is significantly observable when there is no accessibility of an effective treatment. Without a doubt, people choose to continue living and do not opt for taking tests as there is no cure (Weiner & Lipton 2003). Currently, there is one in every ten thousand individuals in United States of America is suffering from HD. Those who are at risk to have inherited HD from a parent number more than 2.5 million. It is important to mention here that both genders are equally affected by this mental impairment disease. According to the worldwide statistics, estimations reveal that 5-10 people out of every 100,000 people will suffer from HD. Children who have a parent with HD have a 50/50 chance to be at risk of inheriting it. The occurrence of the Huntington’s disease has been observed all over the world. However, there are a number of territorial groups in which Huntington’s disease is uncommonly found.
Diagnosis
Only a comprehensive and detailed examination of Huntington’s disease can make sure the completion of an accurate clinical diagnosis. Family history is also checked in detail. In some cases, diagnosis also involves MRI (magnetic response imaging)/CT scans (computerized tomography). However, the findings from such processes are nor sufficient to provide enough information with the help of which a proper diagnosis may be formed. In the similar manner, Huntington’s disease may also be diagnosed by conducting the genetic test of the individual, the results of which may help in the confirmation, ruling out or identification of Huntington’s disease development (DiMaio, Fox & Mahoney 2010).
It is extremely important to mention here that if the HD gene is identified after a positive test result, this finding may not be helpful for the confirmation of HD diagnosis without a neurological examination. This is the reason why it is excessively significant to get checked up by a neurologist who is well-known with the Huntington’s disease. The efficiency of the neurologist counts a lot as HD symptoms are similar to symptoms of Parkinson’s disease, alcoholism etc. Therefore, it is really essential “to confirm that at least one affected member of the family has had the clinical diagnosis confirmed by molecular testing to provide the most accurate genetic counseling, especially if the husband would be considering molecular testing of his own Huntington disease genes” (DiMaio, Fox & Mahoney 2010).
The HD diagnosis may prove to be a relief for some people. They consider it a blessing to know that their lack of memory is a problem and the mystery of why they keep forgetting things is finally resolved. For others, the news regarding HD diagnosis comes as an upsetting shock. A majority of people tend to deny that they have HD even after positive results as it is rather disturbing for them to accept that they have such a rare disease. For such people, the best way to cope up with the reality is to engage in discussions regarding their emotional status. They may share their feelings with a closed one, support group member or therapist.
Genetic Testing
A test was developed soon after the discovery of the Huntington’s disease gene in the year 1993. This test made it possible for people to get confirmed whether they carry the HD-causing gene or not. In the initial phases, the linkage analysis process was used to test people and this needed the family members to get their blood samples tested. However, with the passage of time, new tests were introduced out of which the “direct gene test” is regarded as the most appropriate and authentic. This genetic test only requires the individual who takes the test for the detection of HD gene to give his/her blood sample (Knowles 2007).
Thus, the tests findings revealed that the Huntington disease gene consists of a particular expanded section only found in people who have HD. On the other hand, others who do not suffer from HD have a “tri-nucleotide repeats” section in their DNA. DNA is composed of building blocks i.e. nucleotides which are represented by the alphabets C, A, G and T. As already mentioned, the CAG pattern is repeated forty times or more in people who have Huntington’s disease. The genetic test is used for the analysis of an individual’s DNA whereby the CAG numbers in his/her DNA is counted. The results of the genetic test then make it possible to tell whether there are chances of HD development or not. However, the onset of HD cannot be predicted by genetic testing. It is surprising to know that the genetic disease for Huntington’s disease offer results that are more or less ninety-nine percent accurate all the time (Kirby 1998).
It is an entirely personal matter to decide about undergoing genetic testing, a decision that must not be taken with a light heart. It is required of the family members to not enforce an at-risk individual to go for genetic testing. The process of testing consists of a number of sessions with several professionals. At least one session is meant for having genetic counseling, conducting a neurological exam, an interview with a psychologist, results’ discussion with the individual and family members and follow-up. The genetic test is only a blood test after which diagnosis is made.
Treatment
There are many ways to treat Huntington’s disease although there is still no cure for it. At the same time as no current treatments can be helpful in altering the progression of the Huntington’s disease, there are numerous medications that can be useful in the treatment of common HD symptoms like anxiety, irritation and frustration. Moreover, medications can also help in the lessening of involuntary movements. It is important to mention that a number of drugs can have disturbing side effects. This is the reason why it is the responsibility of the physician to explain them to the patient and his/her family before the beginning of the treatment.
Most of the give drug prescriptions to the patients for treating HD symptoms even when there is no need of it. In majority of cases, it has been observed that people who do not take drugs or take minimal drugs did better than those who took drugs in heavy doses. It happens a lot of time that drugs are helpful at one stage while they stop to have any effect on the patient’s condition at other stages. For such factors, it is often preferable for patients and their families to look for an experienced Huntington’s disease neurologist as not all of them are well-acquainted with it. It is also a good thing to keep the family physician involved in the continuing treatment. A critical role is played by both the HD patients and their families for the monitoring and assessment of the treatment effectiveness.
The treatment also involves physical and speech therapies so it is a good thing if both physical therapist and speech therapist are consulted. Such strategies can turn out to be really helpful in giving a positive influence to the patient and making his/her quality of life improved. In addition, the HD patients need a very well balanced diet as nutrition may have a lasting impact on their physical condition. An exceptional number of calories are needed by the HD patients for the maintenance of their body weight so the importance of diet can never be underestimated in this regard. Patients who are experiencing the last stages of HD find it really helpful to have a really good diet in order to reduce the involuntary movements (by both gaining and losing weight; depending on their physical condition). Nutritional supplements are also suggested by the nutritionists.
Research
Research in finding a cure for Huntington’s disease is the key. A number of ground-breaking theories have been propounded regarding the HD. The gene discovery in 1993 was the main highlight. Since that time, medical scientists have been able to discover certain brain proteins related to huntingtin protein. Currently, research is conducted for finding out the process with which the mentioned proteins combine for producing HD-causing symptoms. Scientists are also keen to find out a way to stop the proteins’ interaction as a main treatment method.
References
DiMaio MS, Fox JE, Mahoney MJ. 2010. Prenatal Diagnosis: Cases and Clinical Challenges [Internet]. 1. Chichester: Wiley-Blackwell; [cited 2013 Nov 10] Available from: http://books.google.com.pk/books?id=Qx2cWaAk2pEC&printsec=frontcover&dq=Prenatal+Diagnosis:+Cases+and+Clinical+Challenges&hl=en&sa=X&ei=9jCCUufnNZOrhQfh0YDACg&ved=0CC0Q6AEwAA#v=onepage&q=Prenatal%20Diagnosis%3A%20Cases%20and%20Clinical%20Challenges&f=false
Knowles J. 2007. Huntington’s Disease [Internet]. 1. New York: Rosen Pub. Group; [cited 2013 Nov 11] Available from: http://books.google.com.pk/books?id=RX2Er7NpMSUC&printsec=frontcover&dq=Huntington’s+Disease&hl=en&sa=X&ei=ameBUqWBDYjBhAfy9YDQCQ&ved=0CEcQ6AEwAw#v=onepage&q=Huntington’s%20Disease&f=false
Lemiere J. 2004. Huntington’s disease: Early Detection and Progression of Cognitive Changes in Patients and Asymptomatic Mutation Carriers [Internet]. Leuven: Leuven University Press; [cited 2013 Nov 11] Available from: http://books.google.com.pk/books?id=vdhgGGgLQSIC&printsec=frontcover&dq=Huntington’s+Disease:+Early+Detection+and+Progression+of+Cognitive+Changes+in+Patients+and+Asymptomatic+Mutation+Carriers&hl=en&sa=X&ei=aGqBUqDzJ6XG7AbVz4CIDQ&ved=0CC0Q6AEwAA#v=onepage&q=Huntington’s%20Disease%3A%20Early%20Detection%20and%20Progression%20of%20Cognitive%20Changes%20in%20Patients%20and%20Asymptomatic%20Mutation%20Carriers&f=false
Roos R. 2010. Huntington’s Disease: A Clinical Review. Orphanet Journal of Rare Diseases [Internet]. [cited 2013 Nov 12] 5:40. Available from: http://www.biomedcentral.com/content/pdf/1750-1172-5-40.pdf
Sheth K. 2013. Huntington’s Disease [Internet]. A.D.A.M. Medical Encyclopedia; [2011 April 30, cited 2013 Nov 11]. Available from: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001775/
Weiner MF, Lipton AM. 2003. The Dementias: Diagnosis, Treatment, and Research [Internet]. 3rd. Washington(DC): American Psychiatric Pub; [cited 2013 Nov 12] Available from: http://books.google.com.pk/books?id=3h3YxCtmoRsC&printsec=frontcover&dq=The+Dementias:+Diagnosis,+Treatment,+and+Research&hl=en&sa=X&ei=LOqBUq6MGuv07Ab3rIGYCA&ved=0CC0Q6AEwAA#v=onepage&q=The%20Dementias%3A%20Diagnosis%2C%20Treatment%2C%20and%20Research&f=false