Parkinson's Parkinson's Genetics and Risk Factors 2 — Questions and Answers
Question 1: The LRRK2 G2019S variant is disproportionately prevalent among which ethnic population with Parkinson's disease?
- East Asian individuals
- Sub-Saharan African individuals
- Ashkenazi Jewish individuals (Correct answer)
- Native American individuals
Correct answer: Ashkenazi Jewish individuals
The LRRK2 G2019S mutation accounts for up to 20% of Parkinson's cases among Ashkenazi Jewish individuals, far higher than in the general population.
Question 2: Mutations in the PRKN (Parkin) gene are most commonly associated with which form of Parkinson's disease?
- Late-onset sporadic PD
- Early-onset familial PD (Correct answer)
- Drug-induced parkinsonism
- Vascular parkinsonism
Correct answer: Early-onset familial PD
PRKN mutations are the most common cause of early-onset familial Parkinson's disease, often presenting before age 40 with slower progression.
Question 3: What classification applies to the majority of Parkinson's disease cases when no definitive genetic or environmental cause is identified?
- Autosomal dominant PD
- Secondary parkinsonism
- Idiopathic Parkinson's disease (Correct answer)
- Juvenile parkinsonism
Correct answer: Idiopathic Parkinson's disease
The majority (~85-90%) of Parkinson's cases are classified as idiopathic, meaning the cause is unknown and likely involves a complex interaction of genetic and environmental factors.
Question 4: Head trauma as a risk factor for Parkinson's disease has been particularly studied in which occupational group?
- Commercial drivers
- Boxers and contact sport athletes (Correct answer)
- Construction workers
- Airline pilots
Correct answer: Boxers and contact sport athletes
Repeated head trauma in boxing and contact sports has been linked to elevated Parkinson's risk, with Muhammad Ali's diagnosis drawing significant public attention to this connection.
Question 5: Chronic occupational exposure to which metal causes manganism, a condition with Parkinson's-like motor features?
- Lead
- Mercury
- Manganese (Correct answer)
- Arsenic
Correct answer: Manganese
Chronic manganese exposure, often seen in welders and miners, causes manganism — a neurological syndrome resembling Parkinson's disease due to damage in the basal ganglia.
Question 6: GBA gene mutations, which cause Gaucher disease in biallelic form, affect Parkinson's disease risk in what way?
- They have no effect on PD risk
- Heterozygous GBA mutations are among the most common PD genetic risk factors (Correct answer)
- GBA mutations only increase PD risk in women
- GBA mutations are protective against PD
Correct answer: Heterozygous GBA mutations are among the most common PD genetic risk factors
Heterozygous GBA mutations are the most common genetic risk factor for Parkinson's disease, increasing lifetime risk approximately 5-fold compared to non-carriers.
Question 7: What is the inheritance pattern of LRRK2-associated Parkinson's disease?
- Autosomal recessive with full penetrance
- Autosomal dominant with reduced penetrance (Correct answer)
- X-linked dominant
- Mitochondrial inheritance
Correct answer: Autosomal dominant with reduced penetrance
LRRK2 mutations follow an autosomal dominant pattern but with reduced (age-dependent) penetrance, meaning not everyone who carries the mutation will develop Parkinson's disease.
Parkinson's Parkinson's Genetics and Risk Factors 2
The LRRK2 G2019S variant is disproportionately prevalent among which ethnic population with Parkinson's disease?