Movement disorders
Many disorders can affect the motor system. In this lesson, we’ll focus on three neurodegenerative diseases as examples.
1) We'll start with a disease covered earlier in the course. Feel free to skip ahead if this is still fresh in your mind, but if not, watch the video and read the article below:
Article: Know Your Brain - Parkinson's Disease
2) Next, we'll discuss two other neurodegenerative diseases that haven't been covered in the course yet: Huntington's disease and amyotrophic lateral sclerosis (ALS).
Article: Know Your Brain - Huntington's disease
3) Finally, answer these questions to test your understanding:
1. This neurodegenerative disease can be traced back to an autosomal dominant mutation in a single gene; the mutation results in a repetitive sequence of three nucleotides---a pattern known as a trinucleotide repeat. The disease can cause a variety of symptoms, including substantial movement-related problems, such as involuntary movements, impaired coordination, and muscle rigidity.
- A. Parkinson's disease
- B. Huntington's disease
- C. Alzheimer's disease
- D. Amyotrophic lateral sclerosis (ALS)
Show Answer
Correct answer: B
Huntington's disease can be traced back to a mutation in the huntingtin (HTT) gene. The mutation causes a high degree of trinucleotide repetition in the gene.
2. If one parent has Huntington's disease, what is the probability that their child will inherit the disease-causing mutation?
- A. 25%
- B. 50%
- C. 75%
- D. 100%
Show Answer
Correct answer: B
The pathology of Huntington’s disease can be traced back to a mutation in a single gene called huntingtin. The mutation that causes Huntington’s disease is a dominant mutation. Thus, if one parent has the disease-causing mutation, their child has a 50% chance of inheriting it.
3. Huntington's disease is caused by a mutation in what gene?
- A. amyloid precursor protein (APP) gene
- B. huntingtin (HTT) gene
- C. tumor protein p53 (TP53) gene
- D. dystrophin (DMD) gene
Show Answer
Correct answer: B
The pathology of Huntington’s disease can be traced back to a mutation in a single gene called huntingtin. The mutation that causes Huntington’s disease is a dominant mutation. Thus, if one parent has the disease, their child has a 50% chance of developing it, too.
4. Which of the following neurodegenerative diseases specifically targets and causes the degeneration of motor neurons?
- A. Parkinson's disease
- B. Alzheimer's disease
- C. amyotrophic lateral sclerosis (ALS)
- D. Huntington's disease
Show Answer
Correct answer: C
ALS is a neurodegenerative disorder, meaning it is characterized by the degeneration and death of neurons. Specifically, the affected neurons in ALS are upper and lower motor neurons. Upper motor neurons extend from the cerebral cortex or brainstem and carry motor information down to the spinal cord. Lower motor neurons extend from the spinal cord or brainstem to skeletal muscle to cause movement.
5. Tremors in Parkinson's disease are typically worse when a patient is:
- A. at rest/not moving
- B. attempting to make a movement (e.g., reaching for something)
- C. they are equally prominent when at rest and when attempting to move
Show Answer
Correct answer: A
The hallmark tremor of Parkinson's disease is often referred to as a "resting tremor." This type of tremor is worse at rest (when not moving), and typically subsides when someone makes a voluntary movement (e.g., reaching for something).
