HD (Huntington’s disease) is also known as Huntington’s chorea. A neurological autosomal dominant condition called Huntington’s chorea is marked by uncontrollable choreatic activities as well as behavioral and cognitive deficits. It is caused by CAG (cytosine, adenine, as well as guanine) trinucleotide duplicates in the HTT gene (Huntingtin) on the arm of the 4p16.3 chromosome.
One such mutation causes the polyglutamine inside the HTT molecule to expand unusually long, which causes neurodegeneration. Additionally, the enlargement makes the HTT molecule extra prone to accumulation and aggregation, which hinders protein function. Patients with HD are frequently in their 30s to 50s when they are diagnosed.
The sooner the start of symptoms, unfortunately, the higher the CAG repetitions. Juvenile Huntington’s disease is marked by learning challenges and also behavioral issues during school and refers to sickness beginning prior to the actual age of twenty.
When a patient exhibits motor, cognitive, or behavioral issues and has a parent who has been diagnosed with HD, the diagnosis is established clinically. DNA testing can then be used to confirm the diagnosis. Pre-manifest assessment can identify gene carriers in patients at high risk for such conditions.
The illness has no known treatment, and as it worsens, affected individuals become increasingly reliant on their caretakers. The goal of treatment is to enhance life quality while reducing problems. The most frequent autopsy report is pneumonia, second by suicide.
Epidemiology
The prevalence of Huntington’s disease, a rare neurological condition, is 2.7 for every 100,000 people worldwide. The frequency varies by more than ten times between different geographic areas, which can be related to variations in case-ascertainment methods and diagnostic standards.
Patients may exhibit enlarged cytosine, adenine, as well as guanine repeats instead of clinical symptoms due to the disease’s adult development. At the bottom end of the cytosine, adenine, as well as guanine repetitions, there is also a partial penetration.
As a result, enlarged repetitions may occur more frequently than previously thought in the overall population. There has consistently been a correlation between a lower frequency among Asians and an increased proportion in Europe, Australia, and North America. The HTT chromosomal haplotypes may be to blame for this.
Anatomy
Pathophysiology
The putamen, cerebral cortex, and caudate degenerating neurons are the main characteristic. Chorea is caused by the basal ganglia’s indirect pathway’s selective degeneration of medium spindle axons that contain enkephalin.
Akinesia and Dystonia arise as a result of further depletion of substance-P-containing medium spindle axons in the pathway. The phenotypic diversity in the patients affected may be explained by the region-specific arrangement of neuronal death in the basal ganglia and cortex.
Multiple processes might take place simultaneously, and there are numerous ideas about the pathophysiology of HD:
Neural aggregates: The Huntington’s disease proteolytic pathway is made up of intracytoplasmic and intranuclear clumps that contain mutant Huntingtin. The ubiquitin-proteosome process may become impaired if these mutated protein clumps build up.
Dysregulation of transcription.
Excitotoxicity is brought on by a combination of elevated glutamate levels and the release of glutamate agonists by cortex afferent neurons.
Alterations in axonal transmission and dysfunctional synapses.
Malfunction of the mitochondria and impaired metabolic activity.
Etiology
HD is an autosomal dominant illness brought on by the Huntingtin gene’s CAG repeats, which have become longer on the short arm of the 4p16.3 chromosome. The gene produces the Huntingtin protein, which is important for post-embryonic development as well as synaptic activity.
It is believed to have anti-apoptotic properties and to guard against the harmful mutation Huntingtin. Some data support the hypothesis that the mutated protein causes both an adding and an impaired function.
There are inclusions within the nucleus and within the cytoplasm of the brain. However, it is unclear whether the inclusions directly contribute to the pathogenesis or whether they are harmful in and of themselves. It is widely known that brain atrophy, especially in the striatum and accompanying significant neuronal death, occurs.
Patients frequently have CAG repetitions between 36 and 55 and the Huntingtin allele. The majority of people with juvenile-onset illness had CAG repetition counts above sixty. Patients who have alleles between 27 and 35 are not disease-phenotypically affected but are more likely to experience repeat instability.
The median age of occurrence, which is determined by the commencement of the first motor manifestation, has an opposite relationship with the length of the repetitions. Seventy percent of the variation in age of occurrence is also influenced by the length of the repetitions. The unpredictability of the cytosine, adenine, as well as guanine repeats throughout spermatogenesis causing the anticipating phenomena, which is visible on the father’s side of inheritance.
The phenomenon of affected kids of a patient with the illness developing the disease at a relatively young age than that of the relation who carried on that allele is common in Huntington’s disease and is brought on by anticipation. Three substantial types of predisposing variables for the disease’s start have been identified by studies.
Risk elements included the Huntingtin gene’s CAG repeat sequences, CAG’s instability, as well as genetic modifications. The lengths of cytosine, adenine, as well as guanine repeats, were discovered to be the most important cause among them. Genetics are crucial to the development of the illness. The disease’s development is also strongly affected by cytosine, adenine, as well as guanine length, particularly when there are neurological, motor, and cognitive issues.
Genetics
Prognostic Factors
Neurodegenerative illness Huntington’s disease has no known treatment. The condition typically progresses for fifteen to twenty years. In addition to revealing the age of clinical start, the cytosine, adenine, as well as guanine repetitions also foretell the age of mortality.
The rate of decline in functional tests, motor, and cognitive increases as cytosine, adenine, as well as guanine repetition sizes increase. The amount of cytosine, adenine, as well as guanine repetitions, has little bearing on how the behavioral signs develop.
Completely penetrant Huntington’s disease homozygotes begin the disease at a similarly aged to heterozygotes, and they may advance the disease more quickly. The disease’s course results in total dependency on day-to-day activities, which eventually necessitates complete care and, ultimately, death. The most common cause of death is pneumonia, which is preceded by suicide.
Clinical History
Physical Examination
Age group
Associated comorbidity
Associated activity
Acuity of presentation
Differential Diagnoses
Laboratory Studies
Imaging Studies
Procedures
Histologic Findings
Staging
Treatment Paradigm
by Stage
by Modality
Chemotherapy
Radiation Therapy
Surgical Interventions
Hormone Therapy
Immunotherapy
Hyperthermia
Photodynamic Therapy
Stem Cell Transplant
Targeted Therapy
Palliative Care
Medication
Future Trends
Media Gallary
References
https://www.ncbi.nlm.nih.gov/books/NBK559166/
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HD (Huntington’s disease) is also known as Huntington’s chorea. A neurological autosomal dominant condition called Huntington’s chorea is marked by uncontrollable choreatic activities as well as behavioral and cognitive deficits. It is caused by CAG (cytosine, adenine, as well as guanine) trinucleotide duplicates in the HTT gene (Huntingtin) on the arm of the 4p16.3 chromosome.
One such mutation causes the polyglutamine inside the HTT molecule to expand unusually long, which causes neurodegeneration. Additionally, the enlargement makes the HTT molecule extra prone to accumulation and aggregation, which hinders protein function. Patients with HD are frequently in their 30s to 50s when they are diagnosed.
The sooner the start of symptoms, unfortunately, the higher the CAG repetitions. Juvenile Huntington’s disease is marked by learning challenges and also behavioral issues during school and refers to sickness beginning prior to the actual age of twenty.
When a patient exhibits motor, cognitive, or behavioral issues and has a parent who has been diagnosed with HD, the diagnosis is established clinically. DNA testing can then be used to confirm the diagnosis. Pre-manifest assessment can identify gene carriers in patients at high risk for such conditions.
The illness has no known treatment, and as it worsens, affected individuals become increasingly reliant on their caretakers. The goal of treatment is to enhance life quality while reducing problems. The most frequent autopsy report is pneumonia, second by suicide.
The prevalence of Huntington’s disease, a rare neurological condition, is 2.7 for every 100,000 people worldwide. The frequency varies by more than ten times between different geographic areas, which can be related to variations in case-ascertainment methods and diagnostic standards.
Patients may exhibit enlarged cytosine, adenine, as well as guanine repeats instead of clinical symptoms due to the disease’s adult development. At the bottom end of the cytosine, adenine, as well as guanine repetitions, there is also a partial penetration.
As a result, enlarged repetitions may occur more frequently than previously thought in the overall population. There has consistently been a correlation between a lower frequency among Asians and an increased proportion in Europe, Australia, and North America. The HTT chromosomal haplotypes may be to blame for this.
The putamen, cerebral cortex, and caudate degenerating neurons are the main characteristic. Chorea is caused by the basal ganglia’s indirect pathway’s selective degeneration of medium spindle axons that contain enkephalin.
Akinesia and Dystonia arise as a result of further depletion of substance-P-containing medium spindle axons in the pathway. The phenotypic diversity in the patients affected may be explained by the region-specific arrangement of neuronal death in the basal ganglia and cortex.
Multiple processes might take place simultaneously, and there are numerous ideas about the pathophysiology of HD:
Neural aggregates: The Huntington’s disease proteolytic pathway is made up of intracytoplasmic and intranuclear clumps that contain mutant Huntingtin. The ubiquitin-proteosome process may become impaired if these mutated protein clumps build up.
Dysregulation of transcription.
Excitotoxicity is brought on by a combination of elevated glutamate levels and the release of glutamate agonists by cortex afferent neurons.
Alterations in axonal transmission and dysfunctional synapses.
Malfunction of the mitochondria and impaired metabolic activity.
HD is an autosomal dominant illness brought on by the Huntingtin gene’s CAG repeats, which have become longer on the short arm of the 4p16.3 chromosome. The gene produces the Huntingtin protein, which is important for post-embryonic development as well as synaptic activity.
It is believed to have anti-apoptotic properties and to guard against the harmful mutation Huntingtin. Some data support the hypothesis that the mutated protein causes both an adding and an impaired function.
There are inclusions within the nucleus and within the cytoplasm of the brain. However, it is unclear whether the inclusions directly contribute to the pathogenesis or whether they are harmful in and of themselves. It is widely known that brain atrophy, especially in the striatum and accompanying significant neuronal death, occurs.
Patients frequently have CAG repetitions between 36 and 55 and the Huntingtin allele. The majority of people with juvenile-onset illness had CAG repetition counts above sixty. Patients who have alleles between 27 and 35 are not disease-phenotypically affected but are more likely to experience repeat instability.
The median age of occurrence, which is determined by the commencement of the first motor manifestation, has an opposite relationship with the length of the repetitions. Seventy percent of the variation in age of occurrence is also influenced by the length of the repetitions. The unpredictability of the cytosine, adenine, as well as guanine repeats throughout spermatogenesis causing the anticipating phenomena, which is visible on the father’s side of inheritance.
The phenomenon of affected kids of a patient with the illness developing the disease at a relatively young age than that of the relation who carried on that allele is common in Huntington’s disease and is brought on by anticipation. Three substantial types of predisposing variables for the disease’s start have been identified by studies.
Risk elements included the Huntingtin gene’s CAG repeat sequences, CAG’s instability, as well as genetic modifications. The lengths of cytosine, adenine, as well as guanine repeats, were discovered to be the most important cause among them. Genetics are crucial to the development of the illness. The disease’s development is also strongly affected by cytosine, adenine, as well as guanine length, particularly when there are neurological, motor, and cognitive issues.
Neurodegenerative illness Huntington’s disease has no known treatment. The condition typically progresses for fifteen to twenty years. In addition to revealing the age of clinical start, the cytosine, adenine, as well as guanine repetitions also foretell the age of mortality.
The rate of decline in functional tests, motor, and cognitive increases as cytosine, adenine, as well as guanine repetition sizes increase. The amount of cytosine, adenine, as well as guanine repetitions, has little bearing on how the behavioral signs develop.
Completely penetrant Huntington’s disease homozygotes begin the disease at a similarly aged to heterozygotes, and they may advance the disease more quickly. The disease’s course results in total dependency on day-to-day activities, which eventually necessitates complete care and, ultimately, death. The most common cause of death is pneumonia, which is preceded by suicide.
https://www.ncbi.nlm.nih.gov/books/NBK559166/
medtigo
Huntington Disease
Updated :
June 28, 2022
HD (Huntington’s disease) is also known as Huntington’s chorea. A neurological autosomal dominant condition called Huntington’s chorea is marked by uncontrollable choreatic activities as well as behavioral and cognitive deficits. It is caused by CAG (cytosine, adenine, as well as guanine) trinucleotide duplicates in the HTT gene (Huntingtin) on the arm of the 4p16.3 chromosome.
One such mutation causes the polyglutamine inside the HTT molecule to expand unusually long, which causes neurodegeneration. Additionally, the enlargement makes the HTT molecule extra prone to accumulation and aggregation, which hinders protein function. Patients with HD are frequently in their 30s to 50s when they are diagnosed.
The sooner the start of symptoms, unfortunately, the higher the CAG repetitions. Juvenile Huntington’s disease is marked by learning challenges and also behavioral issues during school and refers to sickness beginning prior to the actual age of twenty.
When a patient exhibits motor, cognitive, or behavioral issues and has a parent who has been diagnosed with HD, the diagnosis is established clinically. DNA testing can then be used to confirm the diagnosis. Pre-manifest assessment can identify gene carriers in patients at high risk for such conditions.
The illness has no known treatment, and as it worsens, affected individuals become increasingly reliant on their caretakers. The goal of treatment is to enhance life quality while reducing problems. The most frequent autopsy report is pneumonia, second by suicide.
The prevalence of Huntington’s disease, a rare neurological condition, is 2.7 for every 100,000 people worldwide. The frequency varies by more than ten times between different geographic areas, which can be related to variations in case-ascertainment methods and diagnostic standards.
Patients may exhibit enlarged cytosine, adenine, as well as guanine repeats instead of clinical symptoms due to the disease’s adult development. At the bottom end of the cytosine, adenine, as well as guanine repetitions, there is also a partial penetration.
As a result, enlarged repetitions may occur more frequently than previously thought in the overall population. There has consistently been a correlation between a lower frequency among Asians and an increased proportion in Europe, Australia, and North America. The HTT chromosomal haplotypes may be to blame for this.
The putamen, cerebral cortex, and caudate degenerating neurons are the main characteristic. Chorea is caused by the basal ganglia’s indirect pathway’s selective degeneration of medium spindle axons that contain enkephalin.
Akinesia and Dystonia arise as a result of further depletion of substance-P-containing medium spindle axons in the pathway. The phenotypic diversity in the patients affected may be explained by the region-specific arrangement of neuronal death in the basal ganglia and cortex.
Multiple processes might take place simultaneously, and there are numerous ideas about the pathophysiology of HD:
Neural aggregates: The Huntington’s disease proteolytic pathway is made up of intracytoplasmic and intranuclear clumps that contain mutant Huntingtin. The ubiquitin-proteosome process may become impaired if these mutated protein clumps build up.
Dysregulation of transcription.
Excitotoxicity is brought on by a combination of elevated glutamate levels and the release of glutamate agonists by cortex afferent neurons.
Alterations in axonal transmission and dysfunctional synapses.
Malfunction of the mitochondria and impaired metabolic activity.
HD is an autosomal dominant illness brought on by the Huntingtin gene’s CAG repeats, which have become longer on the short arm of the 4p16.3 chromosome. The gene produces the Huntingtin protein, which is important for post-embryonic development as well as synaptic activity.
It is believed to have anti-apoptotic properties and to guard against the harmful mutation Huntingtin. Some data support the hypothesis that the mutated protein causes both an adding and an impaired function.
There are inclusions within the nucleus and within the cytoplasm of the brain. However, it is unclear whether the inclusions directly contribute to the pathogenesis or whether they are harmful in and of themselves. It is widely known that brain atrophy, especially in the striatum and accompanying significant neuronal death, occurs.
Patients frequently have CAG repetitions between 36 and 55 and the Huntingtin allele. The majority of people with juvenile-onset illness had CAG repetition counts above sixty. Patients who have alleles between 27 and 35 are not disease-phenotypically affected but are more likely to experience repeat instability.
The median age of occurrence, which is determined by the commencement of the first motor manifestation, has an opposite relationship with the length of the repetitions. Seventy percent of the variation in age of occurrence is also influenced by the length of the repetitions. The unpredictability of the cytosine, adenine, as well as guanine repeats throughout spermatogenesis causing the anticipating phenomena, which is visible on the father’s side of inheritance.
The phenomenon of affected kids of a patient with the illness developing the disease at a relatively young age than that of the relation who carried on that allele is common in Huntington’s disease and is brought on by anticipation. Three substantial types of predisposing variables for the disease’s start have been identified by studies.
Risk elements included the Huntingtin gene’s CAG repeat sequences, CAG’s instability, as well as genetic modifications. The lengths of cytosine, adenine, as well as guanine repeats, were discovered to be the most important cause among them. Genetics are crucial to the development of the illness. The disease’s development is also strongly affected by cytosine, adenine, as well as guanine length, particularly when there are neurological, motor, and cognitive issues.
Neurodegenerative illness Huntington’s disease has no known treatment. The condition typically progresses for fifteen to twenty years. In addition to revealing the age of clinical start, the cytosine, adenine, as well as guanine repetitions also foretell the age of mortality.
The rate of decline in functional tests, motor, and cognitive increases as cytosine, adenine, as well as guanine repetition sizes increase. The amount of cytosine, adenine, as well as guanine repetitions, has little bearing on how the behavioral signs develop.
Completely penetrant Huntington’s disease homozygotes begin the disease at a similarly aged to heterozygotes, and they may advance the disease more quickly. The disease’s course results in total dependency on day-to-day activities, which eventually necessitates complete care and, ultimately, death. The most common cause of death is pneumonia, which is preceded by suicide.
https://www.ncbi.nlm.nih.gov/books/NBK559166/
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