Huntington’s disease

Huntington’s disease

Description of Huntington’s disease

It is a neurodegenerative (progressive deterioration of nerve tissue) genetic disease with an autosomal dominant transmission from parent to child. This means that if one parent suffers from this disease is 50% chance that he gets sick sooner or later his child. Symptoms, such as involuntary movements, loss of cognitive functions (language, memory, learning and use objects etc.), most often develop from middle age. Unfortunately, there is the tendency to an earlier speech in future generations. So it may not be the exception manifestation of Huntington’s disease in childhood. This particularly happens when the bad gene (allele) is transferred from father to child. The mother was not proved this rule.

This disease is most common in Europe and the US, where its incidence is estimated at 1/20000. Much less common is for example in Asia, including Japan and Africa.

Huntington’s chorea is among triplet disease. Our genetic information is stored in the sequence of building blocks, called nucleotides. All amino acids, from which you produce proteins in our body, are unambiguously given a trio of nucleotides. These are called troika nucleotide triplets triplets and some of the genetic information of human repetitive. In case of Huntington’s disease are repeated triplets CAG and encode the protein huntingtin. In normal humans found about 10 to 26 repetitions CAG triplets. If there are more, a person can fall ill. In the case of 27 to 35 repetitions may further mutations and disease, but does not become anything. If there are 36 to 41 and patients having Huntington’s disease, but do not live to their terrible symptoms in the case of 40 to 55 CAG triplets with disease appear around 40 years of age. If the symptoms occur in childhood will triads more than 60. The reason why we this division is simple, the number of triplets patient can be detected by genetic analysis and subsequent prognosis approximate time of onset of symptoms. Median survival occurrence of symptoms is about 16 years, ie patients die around 55 years of age. The more triplets CAG genetic information is in the patient, the faster the disease appears, it is however important to emphasize that the amount and course of the symptoms completely depend on the number of repeats of CAG triplets.

As I mentioned earlier, it is a neurodegenerative disease. In this case, the parts of the brain are affected basal ganglia, particularly the caudate nucleus. This is a cluster of nerve cells, which are primarily involved in the control of movement. Their activity is particularly high at the beginning of movements recorded. Basal ganglia very cooperate with the cerebral cortex and other brain areas.When the damage is beginning to emerge typical symptoms especially involuntary movements.

Risk factors for Huntington’s disease

If Huntington’s chorea ill with one of the parents, the child has about a 50% chance they get sick too. This occurs in 95 percent of cases. The remaining 5% is a novel mutation in humans predisposed (his parents are healthy). This disease is particularly insidious because it can not influence whether her get sick and when. Basically, the only risk factor as parents, if it so we can not call it. Therefore it is very important to undergo genetic testing in families where the disease occurs.

Prevention of Huntington’s chorea,

Unfortunately, classical prevention for the disease does not exist. When it very simply, if you have a genetic mutation for the disease and become ill. The exceptions are carriers of premutation (27-35 CAG repeat, see Introduction), who very often do not get sick, but they can be affected already by their children. The most important thing is prevention of genetic testing in families where the disease occurs and determine if this mutation does unborn child. If it has, unfortunately, very strongly recommended abortion.

Signs and symptoms of Huntington’s disease

The disease is characterized by the worsening movement disorder, dementia, and emotional and behavioral disorders. As the name suggests, movement disorders dominated chorea. It is an involuntary writhing movements of various localization, which abolishes the patient at rest and in motion, in which the more amplified. These uncontrollable movements will occur on the legs, torso and face. Typical is the inability to maintain a certain status, for example, hand or tongue, lolling patients hold him. Other symptoms include dementia and depression. Very frequent changes and behavioral changes such as irritability, aggression, hypersexuality, but also apathy, just overall personality changes that may precede locomotion or occur simultaneously. Later disorders of speech and swallowing and the resulting salivation. The disease develops irreversible disintegration of personality and cachexia to marasmus (severe form of malnutrition and deprivation).

Diagnosis of Huntington’s disease

The most fundamental is a genetic examination that demonstrates multiplication triplet CAG (see introduction), and we also determined according to the level mutations approximate age, which may manifest disability, but only with less precision. This entire testing is done only under very strict ethical rules. Test may only patients who so strongly stands and fully agrees with the examination.It is totally unacceptable to the patient anything to force or persuade him perhaps. Due to the impossibility of treatment it is necessary to combine these tests with the support of a psychologist and possibly social workers. From auxiliary examinations can be performed CT or magnetic resonance imaging, by which we find malfunction of basal ganglia and particularly the nucleus caudatus.

Treatment of Huntington’s disease

This disease is incurable. You can only suppress choreiform movements medicines that neuroleptics (eg, haloperidol). They may then be taken as necessary antidepressants and anxiolytics. The more important is psychological therapy is not only the patient but the whole family. Social workers are others whom we can ask for help. Despite much research and many drugs in the last stages of testing a treatment for this disease in sight. Hope can give genetic engineering and related fields, which are, unfortunately, particularly when used in humans is still in its infancy. Perhaps in the future will be repaired genes and “cure” mutation. This, however, in future, the problem of the order of decades rather than in the next few years.

Complications of Huntington’s disease

The most profound complications is dysphagia and food intake. The patient lose weight and dramatically deteriorating. Otherwise, all the complications attributed to signs belonging to the disease itself. Especially devastating is a change in behavior when the orderly family member becomes a different person. Often, such a person is egocentric, aggressive, hypersexuální and has a compulsive behavior. Compulsive behavior is activity that patients feel that it must be done, but I have no reason to. Complicating this meeting is more prone to addictions. Last complications are more prone to suicide than the general population average.

Other names: Huntington disease, Huntington’s chorea, chorea major

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