TEST BANK
Medical Genetics
Lynn B. Jorde, John C. Carey, and Michael J. Bamshad
6th Edition
,Table of Contents
Chapter 01 Background and History 1
Chapter 02 Basic Cell Biology-Structure and Function of Genes and Chromosomes 5
Chapter 03 Genetic Variation-Its Origin and Detection 10
Chapter 04 Autosomal Dominant and Recessive Inheritance 14
Chapter 05 Sex-linked and Nontraditional Modes of Inheritance 19
Chapter 06 Clinical Cytogenetics-The Chromosomal Basis of Human Disease 22
Chapter 07 Biochemical Genetics-Disorders of Metabolism 24
Chapter 08 Gene Mapping and Identification 31
Chapter 09 Immunogenetics 42
Chapter 10 Developmental Genetics 52
Chapter 11 Cancer Genetics 63
Chapter 12 Multifactorial Inheritance and Common Diseases 67
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
Chapter 1: Background and History
Jorde: Medical Genetics, 6th Edition
MULTIPLE CHOICE
1. Achondroplasia has a high mutation rate. This is most likely the result of
a. Paternal age effect
b. Maternal age effect
c. Large gene size
d. Methylated CG dinucleotide
e. None of the above
ANS: D
Feedback
A Incorrect. This has not been shown to be the cause of achondroplasia.
B Incorrect. This has not been shown to be the cause of achondroplasia.
C Incorrect. This has not been shown to be the cause of achondroplasia.
D Correct. This has been shown to be the cause of achondroplasia.
E Incorrect. This has not been shown to be the cause of achondroplasia.
2. The effect of mutations in the SHOX gene would best be described as
a. Haploinsufficiency
b. Dominant negative
c. Autosomal recessive
d. Gain of function
e. X-linked recessive
ANS: A
Feedback
A Correct. The effect is best described as haploinsufficiency.
B Incorrect. This does not explain the effects of mutations in the SHOX gene.
C Incorrect. This does not explain the effects of mutations in the SHOX gene.
D Incorrect. This does not explain the effects of mutations in the SHOX gene.
E Incorrect. This does not explain the effects of mutations in the SHOX gene.
3. Which of the following mechanisms is known to cause Prader-Willi syndrome?
a. Chromosome duplication
b. Translocation
c. Uniparental disomy
d. Autosomal trisomy
e. Autosomal monosomy
ANS: C
Feedback
A Incorrect. This would not cause Prader Willi syndrome.
B Incorrect. This would not cause Prader Willi syndrome.
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C Correct. Prader Willi syndrome is effected by genomic imprinting. Thus, a
uniparental disomy could cause the disease.
D Incorrect. This would not cause Prader Willi syndrome.
E Incorrect. This would not cause Prader Willi syndrome.
4. Suppose you have established that a disease gene is closely linked to a marker whose location
is known. Which of the following would not be useful in defining the disease gene's location?
a. Testing for unmethylated CG islands
b. Existence of a chromosome deletion in a patient
c. Existence of trisomy in a patient
d. DNA sequencing
e. Testing for cross-species conservation
ANS: C
Feedback
A Incorrect. This could help you find the disease gene's location.
B Incorrect. This could help you find the disease gene's location.
C Correct. This would not be useful in defining the disease gene's location.
D Incorrect. This could help you find the disease gene's location.
E Incorrect. This could help you find the disease gene's location.
5. Which of the following is least likely to be seen in a patient with Huntington disease?
a. Dementia
b. Affective disorder
c. New mutation
d. Delayed age of onset
e. Loss of motor control
ANS: C
Feedback
A Incorrect. This is seen with Huntington disease.
B Incorrect. This is seen with Huntington disease.
C Correct. This is rarely seen in Huntington disease. It has one of the lowest
known mutation rates of all human disease genes, estimated at approximately 1
per 1 million (per locus per generation).
D Incorrect. This is seen with Huntington disease.
E Incorrect. This is seen with Huntington disease.
6. Which of the following is not a characteristic of osteogenesis imperfecta?
a. Locus heterogeneity
b. Allelic heterogeneity
c. Pleiotropy
d. Imprinting
e. Dominant negative mutation effects
ANS: D
Feedback
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
A Incorrect. This is a characteristic of osteogenesis imperfecta.
B Incorrect. This is a characteristic of osteogenesis imperfecta.
C Incorrect. This is a characteristic of osteogenesis imperfecta.
D Correct. Imprinting is more common with Prader-Willi and Angelman
syndromes.
E Incorrect. This is a characteristic of osteogenesis imperfecta.
7. In which of the following diseases are dominant negative mutation effects seen?
a. Huntington disease
b. Cystic fibrosis
c. Retinoblastoma
d. Marfan syndrome
e. None of the above
ANS: D
Feedback
A Incorrect. One of the above shows dominant negative effects.
B Incorrect. One of the above shows dominant negative effects.
C Incorrect. One of the above shows dominant negative effects.
D Correct. Marfan syndrome shows dominant negative effects.
E Incorrect. One of the above shows dominant negative effects.
8. Which of the following is not true of Fragile X syndrome?
a. It is associated with methylation
b. It can be diagnosed using a karyotype
c. It is caused by a trinucleotide repeat expansion
d. It displays nearly 100% penetrance
e. None of the above
ANS: D
Feedback
A Incorrect. This is true of Fragile X syndrome.
B Incorrect. This is true of Fragile X syndrome.
C Incorrect. This is true of Fragile X syndrome.
D Correct. Fragile X syndrome is an X-linked dominant condition with 80%
penetrance in males and 30% penetrance in females.
E Incorrect. This is true of Fragile X syndrome.
9. Which of the following diseases follow(s) a "2-hit model"?
a. Osteogenesis imperfecta
b. Adult polycystic kidney disease
c. Cystic fibrosis
d. Retinoblastoma
e. B and D
ANS: E
Feedback
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
A Incorrect. Osteogenesis imperfecta does not follow a 2-hit model.
B Incorrect. This is true but is not the only true answer
C Incorrect. Cystic fibrosis does not follow a 2-hit model.
D Incorrect. This is true but is not the only true answer.
E Correct. Retinoblastoma and Adult polycystic kidney disease both follow a 2-hit
model.
10. The recurrence risk for trisomy 13 is increased by
a. Advanced paternal age
b. 13/15 translocation in one of the parents
c. Extensive methylation of chromosome 13
d. Advanced maternal age
e. B and D
ANS: E
Feedback
A Incorrect. Paternal age is usually not a factor in nondisjunction
B Incorrect. This is true but is not the only true answer.
C Incorrect. This does not increase the recurrence risk for trisomy 13.
D Incorrect. This is true but is not the only true answer.
E Correct. Both advanced maternal age and a 13/15 translocation in one of the
parents increases the recurrence risk for trisomy 13.
11. Which of the following is not correct about the XIST gene
a. It is expressed only on the inactive X chromosome
b. It produces an RNA product (which coats the inactivated X chromosome) but no
protein product
c. It is expressed during embryonic development
d. It is expressed at twice the level in females as in males
e. All of the above are true
ANS: D
Feedback
A Incorrect. This is correct about the XIST gene which is responsible for X
inactivation in normal females
B Incorrect. This is correct about the XIST gene which is responsible for X
inactivation in normal females
C Incorrect. This is correct about the XIST gene which is responsible for X
inactivation in normal females
D Correct. The mRNA transcripts are not detected in normal males at all.
E Incorrect. one of the above is false.
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
Chapter 2: Basic Cell Biology: Structure and Function of Genes and Chromosomes
Jorde: Medical Genetics, 6th Edition
MULTIPLE CHOICE
1. Mutation in fibroblast growth factor receptor 3 (FGFR3)
a. Retinoblastoma
b. Achondroplasia
c. Neurofibromatosis type 1
d. Huntington disease
e. Marfan syndrome
ANS: B
Feedback
A Incorrect. Retinoblastoma is caused by mutations in a tumor suppressor on
chromosome 13.
B Correct. Mutations in the fibroblast growth factor receptor 3 do cause
achondroplasia.
C Incorrect. Neurofibromatosis type one is caused by a mutation of the
neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
D Incorrect. Huntington disease is caused by a CAG expanded repeat on the distal
tip of chromosome 4p.
E Incorrect. Marfan patients have mutations of the chromosome 15 gene encoding
fibrillin, a connective tissue protein.
2. Abnormal binding of gene product to GAPDH (enzyme involved in glycolysis)
a. Retinoblastoma
b. Achondroplasia
c. Neurofibromatosis type 1
d. Huntington disease
e. Marfan syndrome
ANS: D
Feedback
A Incorrect. Retinoblastoma is caused by mutations in a tumor suppressor on
chromosome 13.
B Incorrect. Mutations in the fibroblast growth factor receptor 3 cause
achondroplasia.
C Incorrect. Neurofibromatosis type one is caused by a mutation of the
neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
D Correct. This is a characteristic of Huntington disease.
E Incorrect. Marfan patients have mutations of the chromosome 15 gene encoding
fibrillin, a connective tissue protein.
3. phosphorylation of gene product by cyclin-dependent kinases (CDK); binding of gene product
to transcription factors such as E2F
a. Retinoblastoma
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
b. Achondroplasia
c. Neurofibromatosis type 1
d. Huntington disease
e. Marfan syndrome
ANS: A
Feedback
A Correct. The retinoblastoma gene product is phosphorylated by a CDK and then
binds to transcription factors.
B Incorrect. Mutations in the fibroblast growth factor receptor 3 cause
achondroplasia.
C Incorrect. Neurofibromatosis type one is caused by a mutation of the
neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
D Incorrect. Huntington disease involves abnormal binding of gene product to
GAPDH (enzyme involved in glycolysis)
E Incorrect. Marfan patients have mutations of the chromosome 15 gene encoding
fibrillin, a connective tissue protein.
4. Mutations in fibrillin gene
a. Retinoblastoma
b. Achondroplasia
c. Neurofibromatosis type 1
d. Huntington disease
e. Marfan syndrome
ANS: E
Feedback
A Incorrect. The retinoblastoma gene product is phosphorylated by a CDK and
then binds to transcription factors.
B Incorrect. Mutations in the fibroblast growth factor receptor 3 cause
achondroplasia.
C Incorrect. Neurofibromatosis type one is caused by a mutation of the
neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
D Incorrect. Huntington disease involves abnormal binding of gene product to
GAPDH (enzyme involved in glycolysis)
E Correct. Marfan patients have mutations of the chromosome 15 gene encoding
fibrillin, a connective tissue protein.
5. Which of the following could produce an XY female?
a. Deletion of the Sry gene
b. Point mutation in the Sry gene
c. Translocation of the Sry gene to the X chromosome during meiosis in the father
d. None of the above
e. All of the above
ANS: E
Feedback
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
A Incorrect. This is true, but it is not the only true answer.
B Incorrect. This is true, but it is not the only true answer.
C Incorrect. This is true, but it is not the only true answer.
D Incorrect. There are true answers.
E Correct. All of the above could produce an XY female.
6. Which of the following is not a characteristic of cystic fibrosis?
a. Chloride channel defect
b. Hyperabsorption of intracellular sodium
c. Elevated sweat chloride
d. Fibrous ovarian cysts
e. Pancreatic insufficiency
ANS: D
Feedback
A Incorrect. This is a characteristic of cystic fibrosis.
B Incorrect. This is a characteristic of cystic fibrosis.
C Incorrect. This is a characteristic of cystic fibrosis.
D Correct. This is not a characteristic of cystic fibrosis.
E Incorrect. This is a characteristic of cystic fibrosis.
7. Each of the following chromosome abnormalities involves a 20 megabase region of the long
arm of chromosome 5 (5q). Which abnormality is most likely to cause severe disease?
a. Deletion of the region
b. Duplication of the region
c. A balanced translocation involving the region (i.e., in the translocation carrier)
d. Pericentric inversion
e. Paracentric inversion
ANS: A
Feedback
A Correct. This is the most likely to cause severe disease.
B Incorrect. This can cause problems, but they are not as likely to be as severe as a
deletion of the entire gene.
C Incorrect. This can cause problems, but they are not as likely to be as severe as a
deletion of the entire gene.
D Incorrect. This can cause problems, but they are not as likely to be as severe as a
deletion of the entire gene.
E Incorrect. This can cause problems, but they are not as likely to be as severe as a
deletion of the entire gene.
8. Which of the following diseases is a good example of locus heterogeneity?
a. Prader-Willi syndrome
b. Myotonic dystrophy
c. Osteogenesis imperfecta
d. Duchenne muscular dystrophy
e. Hemophilia A
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
ANS: C
Feedback
A Incorrect. Prader-Willi syndrome is a good example of genomic imprinting.
B Incorrect. Myotonic dystrophy is a good example of anticipation.
C Correct. Locus heterogeneity is where genes have more than on discernible
effect. OI effects bones, teeth, and sclera.
D Incorrect. Duchenne muscular dystrophy is an X-linked disease.
E Incorrect. Hemophilia A is an X-linked disease.
9. Why are some autosomal dominant disorders (e.g., Marfan syndrome) seen more commonly
in the offspring of older fathers?
a. Replication errors accumulate as sperm-producing stem cells continue to divide
b. Rate of nondisjunction increases in older males
c. Recombination rates increase in older males
d. All spermatocytes are produced during male embryonic development, so older
males produce older sperm cells
e. None of the above
ANS: A
Feedback
A Correct. This is why some autosomal dominant disorders are seen more
commonly in the offspring of older fathers.
B Incorrect. This is seen in older mothers.
C Incorrect. This is not true.
D Incorrect. This is not true.
E Incorrect. There is a correct answer.
10. A woman with phenotypically normal parents has two brothers with Duchenne muscular
dystrophy. She experiences mild muscle weakness in her legs. Which of the following
mechanisms is most likely to be directly involved?
a. Germline mosaicism
b. Skewed X inactivation
c. Mutation near the pseudoautosomal region of the Y chromosome
d. New mutation in this woman
e. Nondisjunction of her mother's X chromosomes
ANS: B
Feedback
A Incorrect. This wouldn't explain why a heterotroph would manifest the disease.
B Correct. This is most likely to be directly involved.
C Incorrect. A female would not have a Y chromosome.
D Incorrect. If this were the case it would be unlikely that her brothers had the
disease.
E Incorrect. Duchenne muscular dystrophy is not a chromosomal disease.
11. Consider a fetus affected with one of the following conditions. For which condition is
spontaneous loss during pregnancy most likely?
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Medical Genetics
Lynn B. Jorde, John C. Carey, and Michael J. Bamshad
6th Edition
,Table of Contents
Chapter 01 Background and History 1
Chapter 02 Basic Cell Biology-Structure and Function of Genes and Chromosomes 5
Chapter 03 Genetic Variation-Its Origin and Detection 10
Chapter 04 Autosomal Dominant and Recessive Inheritance 14
Chapter 05 Sex-linked and Nontraditional Modes of Inheritance 19
Chapter 06 Clinical Cytogenetics-The Chromosomal Basis of Human Disease 22
Chapter 07 Biochemical Genetics-Disorders of Metabolism 24
Chapter 08 Gene Mapping and Identification 31
Chapter 09 Immunogenetics 42
Chapter 10 Developmental Genetics 52
Chapter 11 Cancer Genetics 63
Chapter 12 Multifactorial Inheritance and Common Diseases 67
,______________________________________________________________________________________________
Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
Chapter 1: Background and History
Jorde: Medical Genetics, 6th Edition
MULTIPLE CHOICE
1. Achondroplasia has a high mutation rate. This is most likely the result of
a. Paternal age effect
b. Maternal age effect
c. Large gene size
d. Methylated CG dinucleotide
e. None of the above
ANS: D
Feedback
A Incorrect. This has not been shown to be the cause of achondroplasia.
B Incorrect. This has not been shown to be the cause of achondroplasia.
C Incorrect. This has not been shown to be the cause of achondroplasia.
D Correct. This has been shown to be the cause of achondroplasia.
E Incorrect. This has not been shown to be the cause of achondroplasia.
2. The effect of mutations in the SHOX gene would best be described as
a. Haploinsufficiency
b. Dominant negative
c. Autosomal recessive
d. Gain of function
e. X-linked recessive
ANS: A
Feedback
A Correct. The effect is best described as haploinsufficiency.
B Incorrect. This does not explain the effects of mutations in the SHOX gene.
C Incorrect. This does not explain the effects of mutations in the SHOX gene.
D Incorrect. This does not explain the effects of mutations in the SHOX gene.
E Incorrect. This does not explain the effects of mutations in the SHOX gene.
3. Which of the following mechanisms is known to cause Prader-Willi syndrome?
a. Chromosome duplication
b. Translocation
c. Uniparental disomy
d. Autosomal trisomy
e. Autosomal monosomy
ANS: C
Feedback
A Incorrect. This would not cause Prader Willi syndrome.
B Incorrect. This would not cause Prader Willi syndrome.
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
C Correct. Prader Willi syndrome is effected by genomic imprinting. Thus, a
uniparental disomy could cause the disease.
D Incorrect. This would not cause Prader Willi syndrome.
E Incorrect. This would not cause Prader Willi syndrome.
4. Suppose you have established that a disease gene is closely linked to a marker whose location
is known. Which of the following would not be useful in defining the disease gene's location?
a. Testing for unmethylated CG islands
b. Existence of a chromosome deletion in a patient
c. Existence of trisomy in a patient
d. DNA sequencing
e. Testing for cross-species conservation
ANS: C
Feedback
A Incorrect. This could help you find the disease gene's location.
B Incorrect. This could help you find the disease gene's location.
C Correct. This would not be useful in defining the disease gene's location.
D Incorrect. This could help you find the disease gene's location.
E Incorrect. This could help you find the disease gene's location.
5. Which of the following is least likely to be seen in a patient with Huntington disease?
a. Dementia
b. Affective disorder
c. New mutation
d. Delayed age of onset
e. Loss of motor control
ANS: C
Feedback
A Incorrect. This is seen with Huntington disease.
B Incorrect. This is seen with Huntington disease.
C Correct. This is rarely seen in Huntington disease. It has one of the lowest
known mutation rates of all human disease genes, estimated at approximately 1
per 1 million (per locus per generation).
D Incorrect. This is seen with Huntington disease.
E Incorrect. This is seen with Huntington disease.
6. Which of the following is not a characteristic of osteogenesis imperfecta?
a. Locus heterogeneity
b. Allelic heterogeneity
c. Pleiotropy
d. Imprinting
e. Dominant negative mutation effects
ANS: D
Feedback
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
A Incorrect. This is a characteristic of osteogenesis imperfecta.
B Incorrect. This is a characteristic of osteogenesis imperfecta.
C Incorrect. This is a characteristic of osteogenesis imperfecta.
D Correct. Imprinting is more common with Prader-Willi and Angelman
syndromes.
E Incorrect. This is a characteristic of osteogenesis imperfecta.
7. In which of the following diseases are dominant negative mutation effects seen?
a. Huntington disease
b. Cystic fibrosis
c. Retinoblastoma
d. Marfan syndrome
e. None of the above
ANS: D
Feedback
A Incorrect. One of the above shows dominant negative effects.
B Incorrect. One of the above shows dominant negative effects.
C Incorrect. One of the above shows dominant negative effects.
D Correct. Marfan syndrome shows dominant negative effects.
E Incorrect. One of the above shows dominant negative effects.
8. Which of the following is not true of Fragile X syndrome?
a. It is associated with methylation
b. It can be diagnosed using a karyotype
c. It is caused by a trinucleotide repeat expansion
d. It displays nearly 100% penetrance
e. None of the above
ANS: D
Feedback
A Incorrect. This is true of Fragile X syndrome.
B Incorrect. This is true of Fragile X syndrome.
C Incorrect. This is true of Fragile X syndrome.
D Correct. Fragile X syndrome is an X-linked dominant condition with 80%
penetrance in males and 30% penetrance in females.
E Incorrect. This is true of Fragile X syndrome.
9. Which of the following diseases follow(s) a "2-hit model"?
a. Osteogenesis imperfecta
b. Adult polycystic kidney disease
c. Cystic fibrosis
d. Retinoblastoma
e. B and D
ANS: E
Feedback
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
A Incorrect. Osteogenesis imperfecta does not follow a 2-hit model.
B Incorrect. This is true but is not the only true answer
C Incorrect. Cystic fibrosis does not follow a 2-hit model.
D Incorrect. This is true but is not the only true answer.
E Correct. Retinoblastoma and Adult polycystic kidney disease both follow a 2-hit
model.
10. The recurrence risk for trisomy 13 is increased by
a. Advanced paternal age
b. 13/15 translocation in one of the parents
c. Extensive methylation of chromosome 13
d. Advanced maternal age
e. B and D
ANS: E
Feedback
A Incorrect. Paternal age is usually not a factor in nondisjunction
B Incorrect. This is true but is not the only true answer.
C Incorrect. This does not increase the recurrence risk for trisomy 13.
D Incorrect. This is true but is not the only true answer.
E Correct. Both advanced maternal age and a 13/15 translocation in one of the
parents increases the recurrence risk for trisomy 13.
11. Which of the following is not correct about the XIST gene
a. It is expressed only on the inactive X chromosome
b. It produces an RNA product (which coats the inactivated X chromosome) but no
protein product
c. It is expressed during embryonic development
d. It is expressed at twice the level in females as in males
e. All of the above are true
ANS: D
Feedback
A Incorrect. This is correct about the XIST gene which is responsible for X
inactivation in normal females
B Incorrect. This is correct about the XIST gene which is responsible for X
inactivation in normal females
C Incorrect. This is correct about the XIST gene which is responsible for X
inactivation in normal females
D Correct. The mRNA transcripts are not detected in normal males at all.
E Incorrect. one of the above is false.
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
Chapter 2: Basic Cell Biology: Structure and Function of Genes and Chromosomes
Jorde: Medical Genetics, 6th Edition
MULTIPLE CHOICE
1. Mutation in fibroblast growth factor receptor 3 (FGFR3)
a. Retinoblastoma
b. Achondroplasia
c. Neurofibromatosis type 1
d. Huntington disease
e. Marfan syndrome
ANS: B
Feedback
A Incorrect. Retinoblastoma is caused by mutations in a tumor suppressor on
chromosome 13.
B Correct. Mutations in the fibroblast growth factor receptor 3 do cause
achondroplasia.
C Incorrect. Neurofibromatosis type one is caused by a mutation of the
neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
D Incorrect. Huntington disease is caused by a CAG expanded repeat on the distal
tip of chromosome 4p.
E Incorrect. Marfan patients have mutations of the chromosome 15 gene encoding
fibrillin, a connective tissue protein.
2. Abnormal binding of gene product to GAPDH (enzyme involved in glycolysis)
a. Retinoblastoma
b. Achondroplasia
c. Neurofibromatosis type 1
d. Huntington disease
e. Marfan syndrome
ANS: D
Feedback
A Incorrect. Retinoblastoma is caused by mutations in a tumor suppressor on
chromosome 13.
B Incorrect. Mutations in the fibroblast growth factor receptor 3 cause
achondroplasia.
C Incorrect. Neurofibromatosis type one is caused by a mutation of the
neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
D Correct. This is a characteristic of Huntington disease.
E Incorrect. Marfan patients have mutations of the chromosome 15 gene encoding
fibrillin, a connective tissue protein.
3. phosphorylation of gene product by cyclin-dependent kinases (CDK); binding of gene product
to transcription factors such as E2F
a. Retinoblastoma
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b. Achondroplasia
c. Neurofibromatosis type 1
d. Huntington disease
e. Marfan syndrome
ANS: A
Feedback
A Correct. The retinoblastoma gene product is phosphorylated by a CDK and then
binds to transcription factors.
B Incorrect. Mutations in the fibroblast growth factor receptor 3 cause
achondroplasia.
C Incorrect. Neurofibromatosis type one is caused by a mutation of the
neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
D Incorrect. Huntington disease involves abnormal binding of gene product to
GAPDH (enzyme involved in glycolysis)
E Incorrect. Marfan patients have mutations of the chromosome 15 gene encoding
fibrillin, a connective tissue protein.
4. Mutations in fibrillin gene
a. Retinoblastoma
b. Achondroplasia
c. Neurofibromatosis type 1
d. Huntington disease
e. Marfan syndrome
ANS: E
Feedback
A Incorrect. The retinoblastoma gene product is phosphorylated by a CDK and
then binds to transcription factors.
B Incorrect. Mutations in the fibroblast growth factor receptor 3 cause
achondroplasia.
C Incorrect. Neurofibromatosis type one is caused by a mutation of the
neurofibromin gene (which may act as a tumor suppressor) on chromosome 17q
D Incorrect. Huntington disease involves abnormal binding of gene product to
GAPDH (enzyme involved in glycolysis)
E Correct. Marfan patients have mutations of the chromosome 15 gene encoding
fibrillin, a connective tissue protein.
5. Which of the following could produce an XY female?
a. Deletion of the Sry gene
b. Point mutation in the Sry gene
c. Translocation of the Sry gene to the X chromosome during meiosis in the father
d. None of the above
e. All of the above
ANS: E
Feedback
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
A Incorrect. This is true, but it is not the only true answer.
B Incorrect. This is true, but it is not the only true answer.
C Incorrect. This is true, but it is not the only true answer.
D Incorrect. There are true answers.
E Correct. All of the above could produce an XY female.
6. Which of the following is not a characteristic of cystic fibrosis?
a. Chloride channel defect
b. Hyperabsorption of intracellular sodium
c. Elevated sweat chloride
d. Fibrous ovarian cysts
e. Pancreatic insufficiency
ANS: D
Feedback
A Incorrect. This is a characteristic of cystic fibrosis.
B Incorrect. This is a characteristic of cystic fibrosis.
C Incorrect. This is a characteristic of cystic fibrosis.
D Correct. This is not a characteristic of cystic fibrosis.
E Incorrect. This is a characteristic of cystic fibrosis.
7. Each of the following chromosome abnormalities involves a 20 megabase region of the long
arm of chromosome 5 (5q). Which abnormality is most likely to cause severe disease?
a. Deletion of the region
b. Duplication of the region
c. A balanced translocation involving the region (i.e., in the translocation carrier)
d. Pericentric inversion
e. Paracentric inversion
ANS: A
Feedback
A Correct. This is the most likely to cause severe disease.
B Incorrect. This can cause problems, but they are not as likely to be as severe as a
deletion of the entire gene.
C Incorrect. This can cause problems, but they are not as likely to be as severe as a
deletion of the entire gene.
D Incorrect. This can cause problems, but they are not as likely to be as severe as a
deletion of the entire gene.
E Incorrect. This can cause problems, but they are not as likely to be as severe as a
deletion of the entire gene.
8. Which of the following diseases is a good example of locus heterogeneity?
a. Prader-Willi syndrome
b. Myotonic dystrophy
c. Osteogenesis imperfecta
d. Duchenne muscular dystrophy
e. Hemophilia A
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Test Bank - Medical Genetics, 6th Edition (Jorde, 2020)
ANS: C
Feedback
A Incorrect. Prader-Willi syndrome is a good example of genomic imprinting.
B Incorrect. Myotonic dystrophy is a good example of anticipation.
C Correct. Locus heterogeneity is where genes have more than on discernible
effect. OI effects bones, teeth, and sclera.
D Incorrect. Duchenne muscular dystrophy is an X-linked disease.
E Incorrect. Hemophilia A is an X-linked disease.
9. Why are some autosomal dominant disorders (e.g., Marfan syndrome) seen more commonly
in the offspring of older fathers?
a. Replication errors accumulate as sperm-producing stem cells continue to divide
b. Rate of nondisjunction increases in older males
c. Recombination rates increase in older males
d. All spermatocytes are produced during male embryonic development, so older
males produce older sperm cells
e. None of the above
ANS: A
Feedback
A Correct. This is why some autosomal dominant disorders are seen more
commonly in the offspring of older fathers.
B Incorrect. This is seen in older mothers.
C Incorrect. This is not true.
D Incorrect. This is not true.
E Incorrect. There is a correct answer.
10. A woman with phenotypically normal parents has two brothers with Duchenne muscular
dystrophy. She experiences mild muscle weakness in her legs. Which of the following
mechanisms is most likely to be directly involved?
a. Germline mosaicism
b. Skewed X inactivation
c. Mutation near the pseudoautosomal region of the Y chromosome
d. New mutation in this woman
e. Nondisjunction of her mother's X chromosomes
ANS: B
Feedback
A Incorrect. This wouldn't explain why a heterotroph would manifest the disease.
B Correct. This is most likely to be directly involved.
C Incorrect. A female would not have a Y chromosome.
D Incorrect. If this were the case it would be unlikely that her brothers had the
disease.
E Incorrect. Duchenne muscular dystrophy is not a chromosomal disease.
11. Consider a fetus affected with one of the following conditions. For which condition is
spontaneous loss during pregnancy most likely?
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