Chorea of ​​Huntington ‘s disease – Huntington Disease Treatment

Chorea of ​​Huntington Huntington ‘s disease , Chorea degenerative , Chorea hereditary , Chorea progressive chronic )

Chorea of ​​Huntington ‘s disease is an inherited, slowly progressive disease of the nervous system characterized by choreic hyperkinesis, mental disorders and progressive dementia. The disease is diagnosed using molecular genetic analysis and brain tomography. No etiotropic treatment has been developed. Patients undergo symptomatic therapy aimed at suppressing hyperkinesis. The prognosis is unfavorable.

General information

Chorea of ​​Huntington is a neurodegenerative disorder with an autoosmono-dominant inheritance, characterized by dementia and motor disorders. The concept of “Huntington’s chorea” also corresponds to: Huntington’s disease, hereditary chorea, degenerative chorea, progressive chronic chorea. The population frequency is 1:10 000. Usually, Huntington’s chorea begins to manifest clinically in the age period from 20 to 50 years. The disease has a poor prognosis, death occurs on average 10-13 years after the onset of the disease.

Causes of Chorea of ​​Huntington ‘s disease

The gene for Huntington’s chorea is located on the short arm of chromosome 4p16.3. It encodes the protein huntingtin, the function of which is not fully understood. However, it is known that the abnormal protein is toxic to the neurons of the brain, which causes the gradual atrophy of cerebral structures. The mode of inheritance is autosomal dominant, the transmission of the defective gene is possible in both the female and male lines.

Pathogenesis

It has been proven that Huntington’s chorea develops as a result of an increase in the number of trinucleotide repeats – cytosine-adenine-guanine, located in the first exon of the gene. The cytosine-adenine-guanine triplet encodes the amino acid glutamine, so an elongated polyglutamine tract is formed in the protein. Forming a kind of “lock-clasp”, the extended polyglutamine region of the huntingtin protein changes its own information and tightly binds to other proteins. As a result, protein aggregation occurs, protein-protein interactions are disrupted, which leads to cell apoptosis.

Symptoms of Huntington’s chorea

Chorea of ​​Huntington manifests itself, as a rule, at the age of 20 to 50. Cases of the juvenile form of the disease are quite rare (no more than 10%); the earliest onset of the disease known today is 3 years. The typical manifestation of Huntington’s chorea in adults is chorea syndrome, which is rare in adolescence. The localization of choreic hyperkinesis falls on the facial muscles, which causes expressive grimaces with protruding tongue, twitching of the cheeks, alternate frowning and / or raising of the eyebrows.

In a number of cases, hyperkinesis was observed in the hands in the form of rapid flexion and extension of the fingers, in the legs – in the form of alternate crossing and extension of the legs to the side. The movements are usually not as fast as in chorea minor , but more difficult, sometimes slow (like athetoid). With the progression of Huntington’s chorea, hyperkinesis intensifies, acquiring the character of athetosis and pronounced dystonia, which subsequently turns into rigidity.

In juvenile forms of Huntington’s chorea, in 50% of cases, the disease manifests itself in the form of bradykinesia and rigidity. Seizures occur in 30-50% of cases (in contrast to adult patients). With the development of the disease in patients, a disorder of speech function occurs. First of all, there are problems with sound pronunciation, the semantic and syntactic structure of speech remains intact until the last stage of the disease. The rate of speech and its rhythm change over time.

Oculomotor disorders are observed in most cases in the early stages of Huntington’s chorea. In patients, the automation of saccading eye movements is impaired: the latent period of the onset of saccading eye movements is lengthened, the speed of translation of the gaze and the accuracy of tracking decrease. With the development of the disease, most patients develop vertical, less often horizontal, sometimes combined nystagmus .

Diagnostics of Chorea of ​​Huntington ‘s disease

On CT or MRI of the brain , atrophy of the heads of the caudate nuclei is determined, which increases as the disease progresses. The diagnosis of Huntington’s chorea is verified at the molecular genetic level . Using the polymerase chain reaction, the number of turns of the cytosine-adenine-guanine triplet in the HD gene is determined. In adult patients, the number of repetitions exceeds 36, with the juvenile form of the disease – 50.

Treatment for Huntington’s chorea

To date, no specific treatment has been developed. Symptomatic treatment by a neurologist is shown , the main goal of which is to combat choreic hyperkinesis. Prescribe drugs that reduce the activity of the dopaminergic systems of the brain (haloperidol, reserpine). The dose of the drug is increased every 2-3 days. The effectiveness of stereotactic surgery for the treatment of Huntington’s chorea has not been proven.

Forecast and prevention

In most cases of Huntington’s chorea, the prognosis for life is not favorable. Death caused by various complications ( pneumonia , congestive heart activity ) occurs after 10-13 years of the course of the disease. Patient life expectancy ranges from 45 to 55 years.

In the absence of examination methods that allow to identify carriers of the pathogen before the manifestation of clinical signs of Huntington’s chorea, medical and genetic consultation presents certain difficulties. Families of patients are not advised to have children in the future.

Leave a Comment