Test Bank Medical Genetics
Question 1
Which of the following best describes the inheritance pattern of autosomal recessive
disorders?
A. Both parents must be carriers for an individual to be affected.
B. An affected individual must have one affected parent.
C. The disorder can skip generations.
D. Males are more frequently affected than females.
Answer: A. Both parents must be carriers for an individual to be affected.
,Rationale: Autosomal recessive disorders require that both parents be carriers for
their offspring to be affected. This pattern means that the disorder can indeed skip
generations if both parents are carriers without showing symptoms.
Question 2
Which genetic phenomenon is characterized by a change in the number of copies of
a specific region of the genome?
A. Point mutation
B. Inversion
C. Copy number variation
D. Translocation
Answer: C. Copy number variation
Rationale: Copy number variation (CNV) refers to changes in the number of copies of
a particular region of the genome, which can affect gene dosage and contribute to
genetic diversity and disease.
Question 3
Which of the following is a common feature of X-linked dominant disorders?
A. Affected males transmit the disorder only to their sons.
B. Both males and females are equally likely to be affected.
C. An affected father will pass the disorder to all his daughters but none of his sons.
D. The disorder is more common in males than in females.
Answer: C. An affected father will pass the disorder to all his daughters but none of
his sons.
,Rationale: In X-linked dominant disorders, affected fathers pass the disorder to all
their daughters (since daughters inherit the father's X chromosome) but none of
their sons (since sons inherit the father's Y chromosome).
Question 4
What is the primary cause of Down syndrome?
A. A single base pair substitution
B. A deletion of a segment of chromosome 21
C. An extra copy of chromosome 21
D. A translocation involving chromosome 21
Answer: C. An extra copy of chromosome 21
Rationale: Down syndrome is primarily caused by an extra copy of chromosome 21,
leading to a total of three copies (trisomy 21). Although translocations involving
chromosome 21 can also cause Down syndrome, the extra chromosome is the most
common cause.
Question 5
Which of the following techniques is most commonly used to detect chromosomal
abnormalities in a prenatal setting?
A. Amniocentesis
B. Polymerase chain reaction (PCR)
C. Fluorescence in situ hybridization (FISH)
D. Western blotting
Answer: A. Amniocentesis
Rationale: Amniocentesis is a prenatal diagnostic procedure used to detect
chromosomal abnormalities by analyzing cells from the amniotic fluid. PCR and FISH
, are techniques used for detecting specific genetic abnormalities, but amniocentesis
provides a broader analysis of chromosomes.Question 6
Which of the following best describes the phenomenon of genomic imprinting?
A. Genetic mutations that occur randomly during DNA replication
B. Differential expression of alleles depending on their parent of origin
C. The duplication of a chromosomal region
D. The inheritance of genes from both parents in equal proportions
Answer: B. Differential expression of alleles depending on their parent of origin
Rationale: Genomic imprinting is a genetic phenomenon where the expression of an
allele depends on whether it was inherited from the mother or the father. This can
lead to different expression patterns for the same genetic variant depending on its
parent of origin.
Question 7
Which type of genetic disorder is characterized by a variable expression and
incomplete penetrance?
A. Autosomal recessive disorders
B. Autosomal dominant disorders
C. X-linked recessive disorders
D. Mitochondrial disorders
Answer: B. Autosomal dominant disorders
Rationale: Autosomal dominant disorders often exhibit variable expressivity (the
range of symptoms) and incomplete penetrance (the likelihood that a person with
the mutation will actually express the disorder). This means that even if an individual
carries the mutation, the severity and presence of symptoms can vary.
Question 1
Which of the following best describes the inheritance pattern of autosomal recessive
disorders?
A. Both parents must be carriers for an individual to be affected.
B. An affected individual must have one affected parent.
C. The disorder can skip generations.
D. Males are more frequently affected than females.
Answer: A. Both parents must be carriers for an individual to be affected.
,Rationale: Autosomal recessive disorders require that both parents be carriers for
their offspring to be affected. This pattern means that the disorder can indeed skip
generations if both parents are carriers without showing symptoms.
Question 2
Which genetic phenomenon is characterized by a change in the number of copies of
a specific region of the genome?
A. Point mutation
B. Inversion
C. Copy number variation
D. Translocation
Answer: C. Copy number variation
Rationale: Copy number variation (CNV) refers to changes in the number of copies of
a particular region of the genome, which can affect gene dosage and contribute to
genetic diversity and disease.
Question 3
Which of the following is a common feature of X-linked dominant disorders?
A. Affected males transmit the disorder only to their sons.
B. Both males and females are equally likely to be affected.
C. An affected father will pass the disorder to all his daughters but none of his sons.
D. The disorder is more common in males than in females.
Answer: C. An affected father will pass the disorder to all his daughters but none of
his sons.
,Rationale: In X-linked dominant disorders, affected fathers pass the disorder to all
their daughters (since daughters inherit the father's X chromosome) but none of
their sons (since sons inherit the father's Y chromosome).
Question 4
What is the primary cause of Down syndrome?
A. A single base pair substitution
B. A deletion of a segment of chromosome 21
C. An extra copy of chromosome 21
D. A translocation involving chromosome 21
Answer: C. An extra copy of chromosome 21
Rationale: Down syndrome is primarily caused by an extra copy of chromosome 21,
leading to a total of three copies (trisomy 21). Although translocations involving
chromosome 21 can also cause Down syndrome, the extra chromosome is the most
common cause.
Question 5
Which of the following techniques is most commonly used to detect chromosomal
abnormalities in a prenatal setting?
A. Amniocentesis
B. Polymerase chain reaction (PCR)
C. Fluorescence in situ hybridization (FISH)
D. Western blotting
Answer: A. Amniocentesis
Rationale: Amniocentesis is a prenatal diagnostic procedure used to detect
chromosomal abnormalities by analyzing cells from the amniotic fluid. PCR and FISH
, are techniques used for detecting specific genetic abnormalities, but amniocentesis
provides a broader analysis of chromosomes.Question 6
Which of the following best describes the phenomenon of genomic imprinting?
A. Genetic mutations that occur randomly during DNA replication
B. Differential expression of alleles depending on their parent of origin
C. The duplication of a chromosomal region
D. The inheritance of genes from both parents in equal proportions
Answer: B. Differential expression of alleles depending on their parent of origin
Rationale: Genomic imprinting is a genetic phenomenon where the expression of an
allele depends on whether it was inherited from the mother or the father. This can
lead to different expression patterns for the same genetic variant depending on its
parent of origin.
Question 7
Which type of genetic disorder is characterized by a variable expression and
incomplete penetrance?
A. Autosomal recessive disorders
B. Autosomal dominant disorders
C. X-linked recessive disorders
D. Mitochondrial disorders
Answer: B. Autosomal dominant disorders
Rationale: Autosomal dominant disorders often exhibit variable expressivity (the
range of symptoms) and incomplete penetrance (the likelihood that a person with
the mutation will actually express the disorder). This means that even if an individual
carries the mutation, the severity and presence of symptoms can vary.
