MVU NURS 629 Advanced Pathophysiology Exam 4 Actual Exam
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Section A: Genetics, Genomics, & Inheritance Patterns (12
Questions)
Q1: A 28-year-old man is diagnosed with Huntington disease. His father was diagnosed
at age 45, and his paternal grandfather died of the disease at age 52. Which inheritance
pattern does this family demonstrate, and what is the probability that this patient's
sibling will inherit the condition?
A. Autosomal recessive; 25% risk for each sibling
B. Autosomal dominant; 50% risk for each sibling
C. X-linked recessive; 50% risk for male siblings, 0% for female siblings
D. Mitochondrial inheritance; 100% risk for all siblings
Correct Answer: B
Rationale: Huntington disease is an autosomal dominant disorder caused by CAG
trinucleotide repeat expansion in the HTT gene on chromosome 4. Each child of an
affected parent has a 50% chance of inheriting the mutation. The phenomenon of
anticipation (earlier onset in successive generations) may occur with repeat expansion.
Option A is incorrect (not recessive); Option C is incorrect (not X-linked); Option D is
incorrect (not mitochondrial).
,Q2: A newborn is diagnosed with cystic fibrosis. Neither parent has clinical symptoms
of the disease. Which molecular mechanism explains the parents' phenotype, and what
is the probability that their next child will also have CF?
A. The parents are unaffected carriers with one mutated allele each; 25% risk for each
subsequent pregnancy
B. The parents have germline mosaicism; 50% risk for each subsequent pregnancy
C. The mother is a carrier and the father has a de novo mutation; 0% risk for subsequent
pregnancies
D. The disease is X-linked and only the mother carries the mutation; 50% risk for male
offspring
Correct Answer: A
Rationale: Cystic fibrosis is autosomal recessive caused by CFTR gene mutations on
chromosome 7. Both parents are asymptomatic carriers (heterozygotes) with one
normal and one mutated allele. Each child has a 25% chance of being affected
(homozygous mutant), 50% chance of being a carrier, and 25% chance of being
unaffected non-carrier. Option B is rare; Option C is incorrect; Option D is incorrect (not
X-linked).
Q3: A 4-year-old boy presents with progressive muscle weakness, frequent falls, and
calf pseudohypertrophy. Genetic testing reveals a deletion in the DMD gene. His mother
has no symptoms, but her CK is mildly elevated. Which inheritance pattern is
demonstrated, and what is the risk to the patient's maternal aunt's future sons?
A. Autosomal dominant; 50% risk
,B. Autosomal recessive; 25% risk
C. X-linked recessive; the aunt has a 50% chance of being a carrier, and if so, 50% of her
sons will be affected
D. Mitochondrial inheritance; 100% risk
Correct Answer: C
Rationale: Duchenne muscular dystrophy is X-linked recessive caused by DMD gene
mutations. The mother is an asymptomatic carrier (manifesting carrier with elevated
CK). Her sister (maternal aunt) has a 50% chance of also being a carrier. If the aunt is a
carrier, each son has a 50% risk of DMD, and each daughter has a 50% chance of being
a carrier. Option A is incorrect; Option B is incorrect; Option D is incorrect.
Q4: A female infant is born with webbed neck, short stature, primary amenorrhea, and
streak ovaries. Karyotype reveals 45,X. Which chromosomal abnormality is present, and
what is the underlying mechanism?
A. Trisomy 21; nondisjunction during meiosis I
B. Monosomy X (Turner syndrome); loss of one sex chromosome, often from paternal
nondisjunction or chromosome loss
C. Klinefelter syndrome; extra X chromosome in a male
D. Cri-du-chat syndrome; deletion of the short arm of chromosome 5
Correct Answer: B
Rationale: Turner syndrome (45,X) is caused by complete or partial absence of one X
chromosome, resulting in monosomy X. Features include short stature, webbed neck,
, lymphedema at birth, primary amenorrhea, streak ovaries, and cardiovascular
anomalies (coarctation, bicuspid aortic valve). Approximately 50% result from paternal
sex chromosome loss. Option A is Down syndrome; Option C is 47,XXY male; Option D
is 5p deletion syndrome.
Q5: A male infant is born with hypotonia, feeding difficulties, and failure to thrive. As he
grows, he develops hyperphagia, obesity, intellectual disability, and hypogonadism.
Genetic testing reveals deletion of the paternal 15q11-q13 region. Which syndrome is
present, and what is the mechanism?
A. Angelman syndrome; maternal deletion of 15q11-q13 with UBE3A mutation
B. Prader-Willi syndrome; paternal deletion of 15q11-q13 with imprinting defect
C. Fragile X syndrome; CGG repeat expansion in FMR1
D. Williams syndrome; microdeletion of 7q11.23
Correct Answer: B
Rationale: Prader-Willi syndrome is caused by loss of paternally expressed genes in
15q11-q13 (paternal deletion in 70%, maternal UPD in 25%, imprinting defect in 5%).
Features: infantile hypotonia, failure to thrive → childhood-onset hyperphagia, obesity,
intellectual disability, hypogonadism, behavioral problems. Angelman syndrome (Option
A) results from maternal deletion of the same region; Option C causes intellectual
disability and autism; Option D causes elfin facies and supravalvular aortic stenosis.
Q6: A 35-year-old woman with a family history of breast and ovarian cancer undergoes
genetic testing. She is found to have a pathogenic variant in BRCA1. Which molecular
function is impaired by this mutation, and what is the lifetime risk of breast cancer?
2026/2027 – Complete Solution with Detailed Rationales | 100%
Verified | Pass Guaranteed – A+ Graded
Section A: Genetics, Genomics, & Inheritance Patterns (12
Questions)
Q1: A 28-year-old man is diagnosed with Huntington disease. His father was diagnosed
at age 45, and his paternal grandfather died of the disease at age 52. Which inheritance
pattern does this family demonstrate, and what is the probability that this patient's
sibling will inherit the condition?
A. Autosomal recessive; 25% risk for each sibling
B. Autosomal dominant; 50% risk for each sibling
C. X-linked recessive; 50% risk for male siblings, 0% for female siblings
D. Mitochondrial inheritance; 100% risk for all siblings
Correct Answer: B
Rationale: Huntington disease is an autosomal dominant disorder caused by CAG
trinucleotide repeat expansion in the HTT gene on chromosome 4. Each child of an
affected parent has a 50% chance of inheriting the mutation. The phenomenon of
anticipation (earlier onset in successive generations) may occur with repeat expansion.
Option A is incorrect (not recessive); Option C is incorrect (not X-linked); Option D is
incorrect (not mitochondrial).
,Q2: A newborn is diagnosed with cystic fibrosis. Neither parent has clinical symptoms
of the disease. Which molecular mechanism explains the parents' phenotype, and what
is the probability that their next child will also have CF?
A. The parents are unaffected carriers with one mutated allele each; 25% risk for each
subsequent pregnancy
B. The parents have germline mosaicism; 50% risk for each subsequent pregnancy
C. The mother is a carrier and the father has a de novo mutation; 0% risk for subsequent
pregnancies
D. The disease is X-linked and only the mother carries the mutation; 50% risk for male
offspring
Correct Answer: A
Rationale: Cystic fibrosis is autosomal recessive caused by CFTR gene mutations on
chromosome 7. Both parents are asymptomatic carriers (heterozygotes) with one
normal and one mutated allele. Each child has a 25% chance of being affected
(homozygous mutant), 50% chance of being a carrier, and 25% chance of being
unaffected non-carrier. Option B is rare; Option C is incorrect; Option D is incorrect (not
X-linked).
Q3: A 4-year-old boy presents with progressive muscle weakness, frequent falls, and
calf pseudohypertrophy. Genetic testing reveals a deletion in the DMD gene. His mother
has no symptoms, but her CK is mildly elevated. Which inheritance pattern is
demonstrated, and what is the risk to the patient's maternal aunt's future sons?
A. Autosomal dominant; 50% risk
,B. Autosomal recessive; 25% risk
C. X-linked recessive; the aunt has a 50% chance of being a carrier, and if so, 50% of her
sons will be affected
D. Mitochondrial inheritance; 100% risk
Correct Answer: C
Rationale: Duchenne muscular dystrophy is X-linked recessive caused by DMD gene
mutations. The mother is an asymptomatic carrier (manifesting carrier with elevated
CK). Her sister (maternal aunt) has a 50% chance of also being a carrier. If the aunt is a
carrier, each son has a 50% risk of DMD, and each daughter has a 50% chance of being
a carrier. Option A is incorrect; Option B is incorrect; Option D is incorrect.
Q4: A female infant is born with webbed neck, short stature, primary amenorrhea, and
streak ovaries. Karyotype reveals 45,X. Which chromosomal abnormality is present, and
what is the underlying mechanism?
A. Trisomy 21; nondisjunction during meiosis I
B. Monosomy X (Turner syndrome); loss of one sex chromosome, often from paternal
nondisjunction or chromosome loss
C. Klinefelter syndrome; extra X chromosome in a male
D. Cri-du-chat syndrome; deletion of the short arm of chromosome 5
Correct Answer: B
Rationale: Turner syndrome (45,X) is caused by complete or partial absence of one X
chromosome, resulting in monosomy X. Features include short stature, webbed neck,
, lymphedema at birth, primary amenorrhea, streak ovaries, and cardiovascular
anomalies (coarctation, bicuspid aortic valve). Approximately 50% result from paternal
sex chromosome loss. Option A is Down syndrome; Option C is 47,XXY male; Option D
is 5p deletion syndrome.
Q5: A male infant is born with hypotonia, feeding difficulties, and failure to thrive. As he
grows, he develops hyperphagia, obesity, intellectual disability, and hypogonadism.
Genetic testing reveals deletion of the paternal 15q11-q13 region. Which syndrome is
present, and what is the mechanism?
A. Angelman syndrome; maternal deletion of 15q11-q13 with UBE3A mutation
B. Prader-Willi syndrome; paternal deletion of 15q11-q13 with imprinting defect
C. Fragile X syndrome; CGG repeat expansion in FMR1
D. Williams syndrome; microdeletion of 7q11.23
Correct Answer: B
Rationale: Prader-Willi syndrome is caused by loss of paternally expressed genes in
15q11-q13 (paternal deletion in 70%, maternal UPD in 25%, imprinting defect in 5%).
Features: infantile hypotonia, failure to thrive → childhood-onset hyperphagia, obesity,
intellectual disability, hypogonadism, behavioral problems. Angelman syndrome (Option
A) results from maternal deletion of the same region; Option C causes intellectual
disability and autism; Option D causes elfin facies and supravalvular aortic stenosis.
Q6: A 35-year-old woman with a family history of breast and ovarian cancer undergoes
genetic testing. She is found to have a pathogenic variant in BRCA1. Which molecular
function is impaired by this mutation, and what is the lifetime risk of breast cancer?
