MGY250 ALL UNITS EXAM QUESTIONS
AND ANSWERS GRADED A+ 2025/2026
RB1 Genetics - ANS Autosomal dominant disease
Two hotspot mutations, but can mutate it infinitely many ways
Deletion of large sections = fewer RB, since you require second allele copy to show the stronger
mutation
Know how the retinoblastoma phenotypes relates to RB1 genetics - ANS - All bilateral + some
unilateral carry mutant RB1 in germline (heritable)
- Most unilateral have both RB1 alleles absent or MYCNamp amplified
Non heritable retinoblastoma tumors are - ANS Identical
Define bilateral - ANS Tumor in both eyes
Define unilateral - ANS Tumor in one eye
Define M1 and M2 mutation - ANS M1 mutation: Primary mutation causing +/-
M2 mutation: Secondary mutation causing -/-
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,How was the physical location of RB1 determined - ANS - Chromosome 13: patients with big
deletions had high risk of retinoblastoma
- Five probes that might be deleted in tumor, found one H38: no band found in Southern blot
- Pulled RNA transcript and found RB1 gene
Importance of early retinoblastoma detection in Kenya - ANS Late diagnosis may result in
need for chemotherapy, expensive drugs and overcrowded radiotherapy lists
Challenge to treating RB in Kenya - ANS Late diagnosis, no genetic testing, limited genetic
counselling
3 facets of providing retinoblastoma medical care according to Dr. Kahaki - ANS Tests
confirming diagnosis
Tests confirming diseases extent
Providing appropriate treatment
Why is there a global disparity in retinoblastoma survival - ANS Most RB occurs in low
resource settings, cannot treat them properly
Barriers to uptake of genetic information - ANS 1. Messenger: nurse/doctor/genetic
counselor training
2. Message: different based on genetic testing availability
3. Barriers: Sociocultural and/or psychosocial
What are the 3 pillars of comprehensive genetics services and how do they apply -
ANS Medical Education, Community Engagement, Patient and Family Counselling
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,Patient and Family Counselling - ANS Conflict with traditional beliefs, thus conduct focus
groups and involve traditional healers
Medical Education - ANS Develop training curriculum and use workshops to test knowledge
retention, as well as scholar programs
Community Engagement - ANS - New Kenyan Community Health Worker (CHW), 1 per 20
families, can disseminate genetic information
- Support mother's decisions and engage families
What is integrated knowledge translation and why is it being used to address barriers to
retinoblastoma treatment - ANS Involves variety of stakeholders to design research
objectives and methodology to help patient experience.
Collaboration can help drive relevant research towards patients to be implemented in long run
Stakeholders of Integrated Knowledge transition - ANS Clinical/Research teams,
Families/survivors, advocates
How does retinoblastoma care vary worldwide - ANS Large amount of low resourced settings
with unavailable help
Different types of results that can be received from genetic testing - ANS 1. Pathogenic
results
2. Secondary finding
3. Variant of Unknown clinical Significance (VUS)
4. Negative results
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, Genetic Testing Result: Pathogenic result - ANS Sequence change in gene causative of
phenotype, has implications for family members
Gene Testing Result: Secondary finding - ANS Only reveal medically actionable, can reveal
child or adult onset disease, has implications for family members
Gene Testing Result: Variant of Unknown clinical Significance (VUS) - ANS Cannot be
interpreted accurately and can't be ruled out as benign or pathogenic
Gene Testing Result: Negative result - ANS Ideally disease free, but not necessarily
Define medically actionable - ANS Some action can be taken for an individual to prevent or
alter a genetic disease
Criteria for judging whether a variant of unknown clinical significance is benign or pathogenic -
ANS 1. 1000 Genomes Frequency
2. Inheritance pattern (de novo vs mutation)
3. Report in literature
4. Conservation of mutated position across species
5. Effect of mutation on protein structure
Reasons why an individual would go see a genetic counsellor - ANS 1. Parents who have just
had a baby with birth defects
2. Parents of a boy diagnosed with Duchenne
3. Family history of genetic condition
4. First cousin couple
5. Repeated pregnancy losses
4 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
AND ANSWERS GRADED A+ 2025/2026
RB1 Genetics - ANS Autosomal dominant disease
Two hotspot mutations, but can mutate it infinitely many ways
Deletion of large sections = fewer RB, since you require second allele copy to show the stronger
mutation
Know how the retinoblastoma phenotypes relates to RB1 genetics - ANS - All bilateral + some
unilateral carry mutant RB1 in germline (heritable)
- Most unilateral have both RB1 alleles absent or MYCNamp amplified
Non heritable retinoblastoma tumors are - ANS Identical
Define bilateral - ANS Tumor in both eyes
Define unilateral - ANS Tumor in one eye
Define M1 and M2 mutation - ANS M1 mutation: Primary mutation causing +/-
M2 mutation: Secondary mutation causing -/-
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,How was the physical location of RB1 determined - ANS - Chromosome 13: patients with big
deletions had high risk of retinoblastoma
- Five probes that might be deleted in tumor, found one H38: no band found in Southern blot
- Pulled RNA transcript and found RB1 gene
Importance of early retinoblastoma detection in Kenya - ANS Late diagnosis may result in
need for chemotherapy, expensive drugs and overcrowded radiotherapy lists
Challenge to treating RB in Kenya - ANS Late diagnosis, no genetic testing, limited genetic
counselling
3 facets of providing retinoblastoma medical care according to Dr. Kahaki - ANS Tests
confirming diagnosis
Tests confirming diseases extent
Providing appropriate treatment
Why is there a global disparity in retinoblastoma survival - ANS Most RB occurs in low
resource settings, cannot treat them properly
Barriers to uptake of genetic information - ANS 1. Messenger: nurse/doctor/genetic
counselor training
2. Message: different based on genetic testing availability
3. Barriers: Sociocultural and/or psychosocial
What are the 3 pillars of comprehensive genetics services and how do they apply -
ANS Medical Education, Community Engagement, Patient and Family Counselling
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,Patient and Family Counselling - ANS Conflict with traditional beliefs, thus conduct focus
groups and involve traditional healers
Medical Education - ANS Develop training curriculum and use workshops to test knowledge
retention, as well as scholar programs
Community Engagement - ANS - New Kenyan Community Health Worker (CHW), 1 per 20
families, can disseminate genetic information
- Support mother's decisions and engage families
What is integrated knowledge translation and why is it being used to address barriers to
retinoblastoma treatment - ANS Involves variety of stakeholders to design research
objectives and methodology to help patient experience.
Collaboration can help drive relevant research towards patients to be implemented in long run
Stakeholders of Integrated Knowledge transition - ANS Clinical/Research teams,
Families/survivors, advocates
How does retinoblastoma care vary worldwide - ANS Large amount of low resourced settings
with unavailable help
Different types of results that can be received from genetic testing - ANS 1. Pathogenic
results
2. Secondary finding
3. Variant of Unknown clinical Significance (VUS)
4. Negative results
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, Genetic Testing Result: Pathogenic result - ANS Sequence change in gene causative of
phenotype, has implications for family members
Gene Testing Result: Secondary finding - ANS Only reveal medically actionable, can reveal
child or adult onset disease, has implications for family members
Gene Testing Result: Variant of Unknown clinical Significance (VUS) - ANS Cannot be
interpreted accurately and can't be ruled out as benign or pathogenic
Gene Testing Result: Negative result - ANS Ideally disease free, but not necessarily
Define medically actionable - ANS Some action can be taken for an individual to prevent or
alter a genetic disease
Criteria for judging whether a variant of unknown clinical significance is benign or pathogenic -
ANS 1. 1000 Genomes Frequency
2. Inheritance pattern (de novo vs mutation)
3. Report in literature
4. Conservation of mutated position across species
5. Effect of mutation on protein structure
Reasons why an individual would go see a genetic counsellor - ANS 1. Parents who have just
had a baby with birth defects
2. Parents of a boy diagnosed with Duchenne
3. Family history of genetic condition
4. First cousin couple
5. Repeated pregnancy losses
4 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
