Parkinson's Parkinson's Genetics and Risk Factors 1 — Questions and Answers
Question 1: Which gene mutation is the most common known genetic cause of familial Parkinson's disease?
- SNCA
- LRRK2 (Correct answer)
- PINK1
- PRKN
Correct answer: LRRK2
LRRK2 (leucine-rich repeat kinase 2) mutations, particularly G2019S, are the most frequently identified genetic cause of familial Parkinson's disease worldwide.
Question 2: Approximately what percentage of Parkinson's disease cases are estimated to be monogenic, caused by a single identifiable gene mutation?
- Less than 1%
- About 10-15% (Correct answer)
- About 40-50%
- About 70-80%
Correct answer: About 10-15%
Roughly 10-15% of Parkinson's cases have a clear monogenic (single-gene) cause, while the majority are idiopathic with complex multifactorial contributions.
Question 3: Which environmental exposure has the strongest epidemiological evidence as a risk factor for Parkinson's disease?
- Air pollution
- Pesticide exposure (Correct answer)
- High sodium diet
- Excessive sunlight
Correct answer: Pesticide exposure
Epidemiological studies consistently link pesticide exposure (particularly paraquat and rotenone) to a significantly increased risk of Parkinson's disease.
Question 4: Which of the following is associated with a REDUCED risk of developing Parkinson's disease?
- Pesticide exposure
- Caffeine consumption (Correct answer)
- Head trauma history
- Rural well-water use
Correct answer: Caffeine consumption
Multiple large studies have found that regular caffeine consumption is inversely associated with Parkinson's disease risk, suggesting a neuroprotective effect.
Question 5: The SNCA gene encodes which protein that aggregates in Lewy bodies, a hallmark of Parkinson's disease?
- Tau protein
- Alpha-synuclein (Correct answer)
- Parkin
- Ubiquitin
Correct answer: Alpha-synuclein
SNCA encodes alpha-synuclein, a presynaptic protein that misfolds and aggregates into Lewy bodies and Lewy neurites in Parkinson's disease.
Question 6: Parkinson's disease incidence rises sharply with age. Which age group has the highest incidence of PD?
- Under 40 years
- 40-50 years
- 51-60 years
- Over 60 years (Correct answer)
Correct answer: Over 60 years
Parkinson's disease is predominantly a disorder of older adults, with incidence increasing substantially after age 60 and peaking in those over 70.
Question 7: Young-onset Parkinson's disease is typically defined as the appearance of motor symptoms before what age?
- 30 years
- 40 years
- 50 years (Correct answer)
- 60 years
Correct answer: 50 years
Young-onset Parkinson's disease (YOPD) is defined as symptom onset between ages 21 and 50, distinguishing it from juvenile PD (before 21) and typical late-onset PD.
Parkinson's Parkinson's Genetics and Risk Factors 1
Which gene mutation is the most common known genetic cause of familial Parkinson's disease?