NUR 3197
Genetics & Genomics
Final Test Review
(Questions & Solutions)
2025
1
,1. A 42-year-old woman tests positive for a pathogenic BRCA1
mutation. According to current US recommendations, which
screening strategy best reduces her breast cancer mortality?
A. Annual mammography beginning at age 40
B. Clinical breast exam every 6 months starting immediately
C. Annual breast MRI starting at age 25 and annual mammography
at age 30
D. Monthly self-breast exam only
Correct ANS: C
Rationale: NCCN guidelines recommend annual MRI at 25–29 and
annual mammography (with MRI) from 30 onward for BRCA carriers to
detect cancers early.
2. A 60-year-old man of Asian descent is prescribed clopidogrel after
percutaneous coronary intervention. Which genetic test result would
most likely predict reduced drug efficacy?
A. CYP2C19 1/ 1
B. CYP2C19 1/ 17
C. CYP2C19 2/ 2
D. CYP2C19 17/ 17
Correct ANS: C
Rationale: The 2 allele encodes a nonfunctional CYP2C19
enzyme. Homozygous 2/ 2 individuals have poor metabolism of
clopidogrel prodrug, reducing its antiplatelet effect.
3. A 55-year-old patient’s colorectal tumor exhibits high
microsatellite instability (MSI-H). Which implication is most
accurate?
A. Tumor likely resistant to immune checkpoint inhibitors
B. Strong possibility of Lynch syndrome and immunotherapy
response
2
, C. MSI-H predicts poor response to 5-fluorouracil
D. MSI assessment has no impact on family screening
Correct ANS: B
Rationale: MSI-H indicates mismatch-repair deficiency, often in
Lynch syndrome, and predicts benefit from PD-1/PD-L1 inhibitors.
4. A 28-year-old woman with a history of major depressive disorder
asks about epigenetic testing. Which description of DNA methylation
is correct?
A. Addition of acetyl groups to histones that upregulates
transcription
B. Addition of methyl groups to cytosine residues that typically
suppresses gene expression
C. Removal of phosphate groups from DNA backbone to initiate
replication
D. Modification exclusive to mitochondrial DNA
Correct ANS: B
Rationale: DNA methylation at CpG sites usually represses gene
transcription by preventing transcription-factor binding.
5. In designing a CRISPR/Cas9 therapy for sickle cell disease, which
off-target effect is of greatest concern?
A. Editing of globin gene promoter only in erythroblasts
B. Unintended cleavage at homologous genomic loci causing
mutations
C. Precise insertion of corrected HBB sequence
D. Exclusive on-target activity
Correct ANS: B
Rationale: Cas9 can bind and cut similar DNA sequences, risking
harmful off-target mutations elsewhere in the genome.
6. A variant of unknown significance (VUS) is found on whole‐exome
3
Genetics & Genomics
Final Test Review
(Questions & Solutions)
2025
1
,1. A 42-year-old woman tests positive for a pathogenic BRCA1
mutation. According to current US recommendations, which
screening strategy best reduces her breast cancer mortality?
A. Annual mammography beginning at age 40
B. Clinical breast exam every 6 months starting immediately
C. Annual breast MRI starting at age 25 and annual mammography
at age 30
D. Monthly self-breast exam only
Correct ANS: C
Rationale: NCCN guidelines recommend annual MRI at 25–29 and
annual mammography (with MRI) from 30 onward for BRCA carriers to
detect cancers early.
2. A 60-year-old man of Asian descent is prescribed clopidogrel after
percutaneous coronary intervention. Which genetic test result would
most likely predict reduced drug efficacy?
A. CYP2C19 1/ 1
B. CYP2C19 1/ 17
C. CYP2C19 2/ 2
D. CYP2C19 17/ 17
Correct ANS: C
Rationale: The 2 allele encodes a nonfunctional CYP2C19
enzyme. Homozygous 2/ 2 individuals have poor metabolism of
clopidogrel prodrug, reducing its antiplatelet effect.
3. A 55-year-old patient’s colorectal tumor exhibits high
microsatellite instability (MSI-H). Which implication is most
accurate?
A. Tumor likely resistant to immune checkpoint inhibitors
B. Strong possibility of Lynch syndrome and immunotherapy
response
2
, C. MSI-H predicts poor response to 5-fluorouracil
D. MSI assessment has no impact on family screening
Correct ANS: B
Rationale: MSI-H indicates mismatch-repair deficiency, often in
Lynch syndrome, and predicts benefit from PD-1/PD-L1 inhibitors.
4. A 28-year-old woman with a history of major depressive disorder
asks about epigenetic testing. Which description of DNA methylation
is correct?
A. Addition of acetyl groups to histones that upregulates
transcription
B. Addition of methyl groups to cytosine residues that typically
suppresses gene expression
C. Removal of phosphate groups from DNA backbone to initiate
replication
D. Modification exclusive to mitochondrial DNA
Correct ANS: B
Rationale: DNA methylation at CpG sites usually represses gene
transcription by preventing transcription-factor binding.
5. In designing a CRISPR/Cas9 therapy for sickle cell disease, which
off-target effect is of greatest concern?
A. Editing of globin gene promoter only in erythroblasts
B. Unintended cleavage at homologous genomic loci causing
mutations
C. Precise insertion of corrected HBB sequence
D. Exclusive on-target activity
Correct ANS: B
Rationale: Cas9 can bind and cut similar DNA sequences, risking
harmful off-target mutations elsewhere in the genome.
6. A variant of unknown significance (VUS) is found on whole‐exome
3
