A comparison between Parkinson’s disease and Huntington’s disease

The central nervous system is involved in both Parkinson’s disease and Huntington’s disease. As a result, they have an impact on how brain cells function, causing symptoms including tremors, limb stiffness, trouble walking or talking, and cognitive or thinking difficulties.

Both disorders are classified as neurodegenerative diseases by the medical community, which refers to conditions in which an individual’s brain or nerve cells gradually degenerate.

Despite the fact that Parkinson’s disease and Huntington’s disease have similar symptoms, they are not the same.

Huntington’s disease is an inherited disease caused by genetic abnormalities passed down from one generation to the next. Experts, on the other hand, feel that Parkinson’s disease is caused by a combination of environmental and genetic variables.

The similarities and contrasts between Parkinson’s disease and Huntington’s disease are examined in this article, as well as how both disorders compare to Alzheimer’s disease.

What do they have in common?

Parkinson’s disease and Huntington’s disease

Parkinson’s disease and Huntington’s disease are both neurodegenerative diseases that affect the central nervous system and cause nerve cells to die slowly.

They both involve the basal ganglia, a brain area that can impair a person’s movement, mental health, and cognitive or thinking ability.

Rigidity and involuntary motions are common motor complaints. Rigidity is defined as stiffness in the limbs that makes movement difficult. As a result of the inactivity, an individual’s muscles and joints may endure pain. Involuntary movements manifest as tremors in Parkinson’s disease and chorea in Huntington’s disease. Chorea is a term used to describe involuntary, unexpected, and dance-like motions.

There is no treatment for either ailment, and there are currently no medications that can alter the course of the disease. As a result, therapeutic options are designed to alleviate symptoms.

The differences

Although the basal ganglia are involved in both Huntington’s disease and Parkinson’s disease, the origins of each disease are distinct.

Parkinson’s disease is caused by the loss of dopaminergic neurons in the substantia nigra, a portion of the brain. These neurons are specialized cells that manufacture dopamine, a chemical that aids neuronal communication. Parkinson’s disease is thought to be caused by a combination of genetic and environmental factors, according to experts.

Huntington’s disease is a hereditary disorder caused by a mutation in the Huntingtin (HTT) gene. A gene mutation causes aberrant protein to be produced. The creation of aberrant protein is caused by the increase of the cytosine-adenine-guanine (CAG) trinucleotide in the HTT gene. The bigger the number of CAG repeats, the younger the onset age and the more severe the disease.

Huntington’s disease is also an autosomal dominant disorder, which means that it can be caused by a change in just one of the two copies of the HTT gene. When a person with Huntington’s disease has offspring, each of their children has a one-in-two risk of receiving the faulty gene and acquiring the disease. The majority of people with Huntington’s disease have a parent who has the disease.

Basal ganglia and its role

Parkinson’s disease affects the substantia nigra, a component of the brain’s basal ganglia. The substantia nigra produces dopamine, a chemical that keeps nerves communicating.

Movement is aided by dopamine and another neurotransmitter, acetylcholine. The progressive loss of cells in the substantia nigra causes decreased dopamine production in Parkinson’s disease. Doctors are baffled as to why this occurs.

Dopamine deficiency causes an imbalance between dopamine and acetylcholine. This imbalance affects nerve communication, resulting in uncontrollable motor symptoms.

Overstimulation of the motor cortex can result in chorea, which is characterized by uneven, jerky movements.

Symptoms

Huntington’s disease and Parkinson’s disease both induce symptoms that can have a significant impact on a person’s life, but there are key distinctions between the two diseases.

Huntington’s disease

Huntington’s disease can produce a variety of movement issues, including chorea (unusual jerking and writhing movements).

Huntington’s disease results in cognitive abnormalities as well as behavioral and mental health issues. They may struggle with the following:

  • organization
  • impulse control
  • self-awareness
  • thought and word processing
  • learning

Additionally, mood problems may manifest as:

  • irritability or sadness
  • insomnia
  • suicidal thoughts
  • social withdrawal
  • hallucinations

Individuals may also develop obsessive-compulsive disorder (OCD), bipolar disorder, and mania.

Parkinson’s disease

Parkinson’s disease causes tremors in the chin or one hand. When the condition progresses, the tremor may affect both sides of the body.

Handwriting can also change, becoming smaller or more cluttered.

People may also experience other symptoms, such as:

  • loss of smell
  • hunching over
  • rigidity
  • bradykinesia, which is slow or difficult movement
  • hypophonia, or a soft voice
  • sleep abnormalities, such as REM sleep behavior disorder, restless leg syndrome, daytime sleepiness, and sleep attacks

Bradykinesia can appear in a variety of ways. Starting an action, such as getting out of bed, may be challenging for a person. Any physical exertion might become slow, making ordinary tasks challenging for people with Parkinson’s disease.

Treatment

Because neither Huntington’s nor Parkinson’s disease have a cure, treatments try to alleviate symptoms and assist patients maintain the highest possible quality of life.

Huntington’s

The way a person manages their Huntington’s disease is determined by their symptoms. To treat chorea, the American Academy of Neurology (AAN) recommends tetrabenazine (Xenazine), amantadine (Gocovri), or riluzole (Rilutek).

Doctors may give selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs) if the person is suffering from mental health issues such as anxiety, depression, or OCD.

Parkinson’s

For Parkinson’s disease, there is no single conventional treatment, and none that can reverse the illness’s consequences. Instead, doctors make recommendations based on a patient’s symptoms.

Doctors may prescribe a variety of drugs to alleviate symptoms, with levodopa (Sinemet) being the most common. Dopamine agonists and monoamine oxidase-B inhibitors are two more drugs that may help delay the development of motor problems.

Alzheimer’s disease vs. Parkinson’s and Huntington’s disease

Alzheimer’s disease, like Huntington’s and Parkinson’s diseases, is a neurodegenerative disease that affects the brain. All three diseases can be debilitating and have a significant influence on a person’s everyday life.

Alzheimer’s disease, on the other hand, largely affects a person’s memory, thoughts, and conduct, rather than movement, like Huntington’s disease and Parkinson’s disease do.

Huntington’s disease, like Alzheimer’s disease, can produce severe cognitive difficulties, albeit this is not a prominent hallmark of Parkinson’s disease.

Is it possible to prevent these conditions?

No, it is not possible to prevent these conditions.

Huntington’s disease is a genetic condition caused by a mutation in a person’s DNA. Doctors are unable to prevent sickness since they cannot alter a person’s genetic composition. Furthermore, there are presently no treatments available to stop or decrease the growth of Huntington’s disease.

Parkinson’s disease is thought to have a genetic component, according to experts. However, because certain environmental factors might influence a person’s risk of having the disease, lifestyle changes may help to lower the risk. These may include the following:

  • avoiding toxins
  • avoiding pesticides
  • avoiding exposure to metals
  • protecting against traumatic brain injuries

Individuals can also consider obtaining frequent physical activity, since this healthy habit may help maintain the brain’s dopamine levels, according to a 2018 review.

Conclusion

Parkinson’s disease and Huntington’s disease are neurodegenerative diseases that affect the brain’s basal ganglia.

Huntington’s disease is a genetic condition caused by a defective gene inherited from a parent. Parkinson’s disease, on the other hand, can be caused by a range of genetic and environmental causes.

In both cases, involuntary motor signs are present. People with Parkinson’s disease may have rigidity and slower movements, whereas those with Huntington’s disease may also have cognitive and psychosocial symptoms.

Both diseases have no cures, therefore therapy focuses on easing symptoms and managing any mental health issues that may arise, especially in the case of Huntington’s disease.

Sources

  • https://www.parkinson.org/understanding-parkinsons/10-early-warning-signs
  • https://www.ncbi.nlm.nih.gov/books/NBK559166/
  • https://www.sciencedirect.com/science/article/pii/S0006295218300492
  • https://rarediseases.info.nih.gov/diseases/6677/huntington-disease
  • https://www.ncbi.nlm.nih.gov/books/NBK536722/
  • https://www.medicalnewstoday.com/articles/parkinsons-vs-huntingtons
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897963/
  • https://www.nia.nih.gov/health/parkinsons-disease
  • https://www.aafp.org/afp/2006/1215/p2046.html
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3221774/
  • https://www.parkinson.org/Understanding-Parkinsons/Treatment
  • https://www.alz.org/alzheimers-dementia/what-is-alzheimers