A rare genetic neurological condition called Huntington’s disease (HD) has significant adverse effects on a person’s physical, mental, and emotional health. Thousands of people worldwide suffer from this severe disease, which is defined by a progressive degeneration of brain cells.
The purpose of this article is to give a thorough understanding of Huntington’s disease by going over the condition’s symptoms, causes, and preventative measures.
Huntington’s Disease
Huntington’s disease is a genetic disorder that brings about the progressive deterioration of nerve cells in the brain. A person’s functional abilities are affected by this breakdown, which often leads to motion, cognitive, and mental health issues. George Huntington is the doctor who first described HD in 1872.
A genetic mutation on chromosome 4 mainly causes Huntington’s disease. The CAG repeat is a DNA segment that is involved in this mutation. This segment repeats 10–35 times on average, but in HD patients, it can repeat 36–120 times or more.
Symptoms of Huntington’s disease
These are the signs and symptoms of Huntington’s disease, which include a range of motor, cognitive and neurological disorders that gradually decrease the person’s quality of life:
Motor Symptoms
Chorea, or involuntary jerky movements affecting the face, limbs, and other body parts, is one of the primary symptoms of Huntington’s disease (HD). Walking, eating, and speaking can all be impeded by these erratic movements.
Dystonia is a condition in which people contract and twist their muscles uncontrollably, resulting in abnormal postures. As the disease progresses, there may also be issues with coordination, balance, and fine motor skills, which can make mundane tasks like writing or sewing clothes difficult.
Cognitive Symptoms
Cognitive skills are also affected by Huntington’s disease, including memory loss and issues with focus, logic, and problem-solving. The ability to carry out tasks at home or work can gradually decrease in some people because of memory loss.
Reduced ability in social skills, impulsivity, and irritability are examples of common behavioural and personality changes. Depression and anxiety are also common, affecting emotional well-being and quality of life.
Psychiatric Symptoms
A wide range of emotional and behavioural deviations, such as depression, anxiety, and irritability, are included in psychiatric symptoms associated with Huntington’s disease (HD). These symptoms not only appear as depressive episodes but also change as the disease progresses and may become more severe as the brain deteriorates.
It emphasises the complex connection between neurological decline and emotional well-being in HD patients. These psychiatric symptoms have a profound impact on people’s ability to manage daily tasks, maintain social interactions, and sustain overall quality of life.
Causes of Huntington’s disease
Here are the leading causes of Huntington’s disease:
Genetic Mutation
A genetic mutation in the HTT gene, that is found on chromosome 4, is the main cause of Huntington’s disease. The huntingtin protein, involved in a variety of cellular processes in the brain, is typically produced by this gene. The mutation that causes Huntington’s disease is caused by an aberrant expansion of the HTT gene’s CAG (cytosine-adenine-guanine) trinucleotide repeat sequence.
The average range of CAG repeats in unaffected individuals is 10–35. However, this repeat sequence increases to 36 or more instances in people who have Huntington’s disease. Notably, an increased number of CAG repeats tends to worsen the disease. An altered huntingtin (HTT) protein produced as a result of the enlarged CAG repeat is dangerous to brain neurons.
Inheritance
Huntington’s disease develops in an autosomal dominant manner. It indicates that the disease can occur in a person who inherits just one copy of the mutated HTT gene (one mutated allele) from either parent. Each child of a parent with a mutated HTT gene has 50% chances of inheriting the mutation and a tendency to get Huntington’s disease.
As compared to this inheritance pattern, recessive genetic disorders require the inheritance of a mutated gene from both parents for the disorder to become visible. Huntington’s disease has an autosomal dominant inheritance pattern, which means that affected individuals have a likelihood of transmitting the disease to their children.
Pathophysiology
The pathophysiology of Huntington’s disease involves progressive neurodegeneration in specific areas of the brain. A key component of this process is the mutated huntingtin protein, which is created as a result of the HTT gene’s increased CAG recurrence.
The mutant huntingtin protein’s tendency to combine or merge collectively within neurons is one of its main effects. These aggregates cause a variety of cellular dysfunctions, including the eventual death of neuronal cells.
This process mainly affects the cortex and basal ganglia. These areas of the brain are essential for cognitive function, motor control, and coordination. The characteristic motor symptoms (dystonia and chorea) and cognitive impairments (memory loss and executive dysfunction) seen in Huntington’s disease patients are explained by the degeneration of neurons in these areas.
Preventing Techniques for Huntington’s Disease
The following are methods for preventing Huntington’s disease that are intended to lower the chance of developing and worsening the disease. These include:
Genetic Counselling
For those who have a family history of Huntington’s disease, genetic counselling is essential. It helps in gaining an understanding of the likelihood that they will either inherit or pass on the mutant HTT gene. Counsellors can provide information on inheritance patterns, the nature of the disease, and the effects of genetic testing.
Counselling helps people make well-informed decisions about reproductive and family planning. It offers a secure environment for them to talk about how the disease might affect their lives and the lives of their families.
Predictive Genetic Testing
Individuals who are at risk can find out if they have the HTT gene mutation through predictive genetic testing even before symptoms appear. This knowledge can greatly benefit making decisions in life, such as managing healthcare, planning a family, and choosing a career.
By looking into preventive reproductive options, one can lower the risk of passing on the mutation and make decisions about whether to have biological children according to their genetic status.
Gene Therapy
The goal of gene therapy for Huntington’s disease is to lessen the production of the dangerous mutant huntingtin protein by mutating or silencing the HTT gene. In clinical trials, methods like antisense oligonucleotides (ASOs) and RNA interference (RNAi) are being examined to block the gene’s activity.
Furthermore, the HTT gene mutation can be directly corrected at the DNA level with the help of CRISPR/Cas9 technology. These approaches, while still in the experimental stage, provide hope for future treatments that target the progression of the disease.
Stem Cell Therapy
Stem cell therapy seeks to recover lost functions in patients with Huntington’s disease by determining the potential to employ stem cells to replace damaged neurons in the brain. The ultimate objective is to replace damaged or lost neurons in the brain to restore neural functions, which will enhance motor control and cognitive function.
Neuroprotective Agents
The development of neuroprotective agents aims to protect neurons from the damaging effects of the mutant huntingtin protein, which is responsible for the advancement of Huntington’s disease. By protecting brain cells, these chemicals seek to reduce the growth of the disease and enhance the quality of life for patients. Many medications are presently being tested in clinical settings to see how well they provide neuroprotection.
Neurostimulation
A treatment option for the severe motor symptoms of Huntington’s disease is neurostimulation, specifically Deep Brain Stimulation (DBS). To treat symptoms like stiffness and uncontrolled movements, DBS involves implanting electrodes in particular brain regions to modulate abnormal brain activity.
According to research, DBS may considerably enhance motor function in those who are affected. This method presents a viable choice for improving the quality of life for those experiencing severe motor symptoms.
Conclusion
In conclusion, Huntington’s disease is a challenging and complex disease that has a notable impact on people and families. The disease can be managed more skillfully, even though there is presently no cure, by being aware of the causes, symptoms, and possible preventive measures.
