Introduction:
Huntington’s disease is a neurological condition. It is an inherited condition that is caused by a genetic mutation. The disease affects different brain parts, including behavior, movement, and cognition. It impacts the daily activities of life, such as reasoning, thinking, walking, and talking. The condition can be fatal or complicated. It is a progressive brain disorder that causes emotional problems, uncontrolled movements, and cognitive impairment(the person has trouble remembering, learning new things, or making new decisions). As the disease progresses, it causes depression, irritability, poor coordination, and involuntary movements. The other symptoms of juvenile Huntington’s disease include frequent falling, slow movements, slurred speech, and rigidity. A less common form of Huntington’s disease, juvenile form, begins in childhood or adolescence. In these children, school performance declines, and seizures can occur in 30 % to 50 % of children. The juvenile form tends to progress more rapidly than the adult form. Parkinson’s disease occurs due to the damage of nerve cells or neurons in the substantia nigra of the brain.
What Are the Causes of Huntington’s Disease and Parkinson’s Disease?
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An inherited difference in one gene causes Huntington's disease. It is an autosomal dominant disorder. The person will need only one copy of the nontypical gene to develop the condition.
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The signs and symptoms of Parkinson's disease are due to the nerve cells in the basal ganglia. The basal ganglia is an area of the brain that controls movement. The neurons that produce dopamine are damaged. When the nerve cells are damaged or impaired, they produce less dopamine, because of which there are movement problems associated with the disease. Some cases are due to hereditary, and some have specific genetic variants. A person inherits two copies of a gene, one from each parent.
How Are Parkinson’s Disease and Huntington’s Disease Similar?
Both Huntington's and Parkinson's disease involve the central nervous system. It is a neurodegenerative disease with damage to the brain's nerve cells, and they both affect the brain's basal ganglia. They affect the individuals' mental health, cognition (the process of acquiring knowledge), movement, and thinking. It causes stiffness, rigidity, and involuntary movements. Rigidity causes symptoms such as limb stiffness, making it challenging to move and causing muscle and joint pain. The involuntary movements are presented as tremors (shaking of the body) in Parkinson's disease. In Huntington's disease, involuntary movements are presented as chorea. Chorea refers to unpredictable, involuntary, and dance-like movements.
What Is the Difference Between Parkinson’s Disease and Huntington’s Disease?
Huntington’s disease and Parkinson’s disease both involve the basal ganglia but the causes of each disease are different.
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Huntington's disease is a genetically inherited disorder involving the Huntingtin (HTT) gene. The defect process is cytosine-adenine-guanine (CAG) expansion in the HTT gene. The affected gene produces abnormal protein.
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The higher the number of CAG expansion, the faster the onset and the higher the severity of the disease.
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Huntington's disease is an autosomal dominant disorder. There is a mutation in only one of the two copies of the HTT gene that cause the disease.
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Parents with Huntington's disease have a 1 in 2 chance of passing it to their children because the affected children have an affected parent.
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The brain's basal ganglia handle complex processes affecting the entire body. They play several functions, such as emotional processing and learning. The connections help different areas of the brain to work together. The basal ganglia in the brain interact with other parts of the brain. It controls voluntary movements of the body.
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Dopamine and acetylcholine are both neurotransmitters that are involved in the movement. The damage of nerve cells in the substantia nigra causes decreased dopamine production.
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The low level of dopamine creates an imbalance between dopamine and acetylcholine. This imbalance disrupts the communication between nerves, leading to uncontrolled involuntary motor symptoms.
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The later stages of Huntington's disease can cause dementia. In addition, it can lead to loss of memory and personality changes.
What Are the Signs and Symptoms of Parkinson’s Disease?
The signs and symptoms of the disease are:
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Tremors (rhythmic shaking movements).
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Balance and coordination problems.
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Changes in speech.
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Muscle spasms or cramps.
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Trouble chewing or swallowing.
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Changes in posture.
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Hyperhidrosis (excessive sweating).
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Disrupted sleeping patterns.
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Issues with urination.
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Rigidity (stiffness of the arms or legs).
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Bradykinesia (slow movement).
What Are the Signs and Symptoms of Huntington’s Disease?
Huntington’s disease can cause movement problems and chorea, which is unusual jerking and writhing movements. Huntington’s disease lead to cognitive changes and behavioral and mental health symptoms. They have difficulties with the following:
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Suicidal thoughts.
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Social withdrawal.
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Hallucinations.
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Organization.
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Impulse control.
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Self-awareness.
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Thought and word processing.
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Learning.
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Irritability or sadness.
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Insomnia.
What Are the Treatments for the Condition?
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Exercise strengthens muscles and improves balance, flexibility, and coordination.
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Massage therapy to reduce tension.
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Yoga therapy increases stretching and flexibility.
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Slow-paced movements and exercises that target specific muscle groups can improve strength and help with balance and coordination.
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Occupational therapists help treat disabled patients through the therapeutic use of daily activities. Occupational therapy provides relief and independence by teaching individuals how to care for themselves. It teaches how to function to the best of their abilities.
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A multidisciplinary approach that consists of a psychiatrist, neurologist, genetic counselor, speech therapist, and occupational therapist can help the patient recover.
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To help with emotional problems, antidepressants, antipsychotic drugs, and mood-stabilizing drugs are prescribed.
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To control chorea, doctors prescribe Deutetrabenazine, Tetrabenazine, and Haloperidol.
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Levodopa is the precursor to dopamine. Levodopa is used as a replacement for dopamine in treating Parkinson’s disease.
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Dopamine agonists such as Pramipexole, Rotigotine, and Ropinirole act like dopamine in the brain. Dopamine agonists are the first treatment choice for Parkinson's because they have fewer side effects. They act like dopamine in the brain. But they have short-term side effects such as dizziness, light-headedness, nausea, vomiting, and hallucinations.
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MAO-B inhibitors like Selegiline, Safinamide, and Rasagiline block the brain chemicals that break down dopamine.
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Catechol oxidase methyl transferase (COMT) is an enzyme that oxidizes neurotransmitters. COMT inhibitors are Entacapone, Opicapone, and Tolcapone. A chemical in the body called COMT blocks the action of levodopa. The COMT inhibitor drugs block COMT action so the brain can use levodopa more effectively.
Conclusion:
Huntington's and Parkinson's disease are neurodegenerative disorders involving the brain's basal ganglia. Both involve problems with involuntary movements. In Huntington's disease, people experience psychological and cognitive problems, whereas, in Parkinson's disease, people experience rigidity and slow movements. Chromosome 4 mutations cause Huntington's disease, although Parkinson's disease is not commonly considered a genetic condition. According to the autosomal dominant inheritance pattern for Huntington's Disease, each child has a 50 % chance of getting Huntington's disease if one parent carries the mutant gene. On the other hand, it is believed that a combination of genetic and environmental factors contribute to Parkinson's disease. While cognitive impairment can occur in both conditions, it is more frequent and severe in Huntington's disease.
