NSG 3280 Pathophysiology 1 - EXAM 4 Genetics
and Genetic Disorders 2026!!
1. The nurse is caring for a client who has Huntington's disease. The nurse understands that this
autosomal dominant disorder affects which of the following organ systems?
A. Neurologic
B. Gastrointestinal
C. Muscular
D. Endocrine
ANSWER: A. Neurologic
Rationale: Huntington's disease is a progressive neurodegenerative disorder that primarily affects the
basal ganglia and cerebral cortex, leading to motor, cognitive, and psychiatric symptoms. It is caused by
a CAG trinucleotide repeat expansion in the HTT gene on chromosome 4.
Option B Rationale: While gastrointestinal symptoms such as dysphagia and weight loss can occur
secondary to neurologic impairment, the primary pathophysiology involves the nervous system, not the
gastrointestinal system itself.
Option C Rationale: Although choreiform movements and motor dysfunction are hallmark features,
these result from neurologic degeneration rather than primary muscular pathology. The muscles
themselves are structurally normal.
Option D Rationale: While some endocrine disturbances may occur secondary to hypothalamic
involvement, the primary disorder affects neurologic function, making this option incorrect.
,2. The nurse is interviewing a female client who is currently taking thalidomide and just learned they are
5 weeks pregnant. Which of the following should the nurse be concerned about?
A. Teratogenesis
B. Microcephaly
C. Fetal alcohol spectrum disorders
D. Cytomegalovirus
ANSWER: A. Teratogenesis
Rationale: Thalidomide is a well-known teratogen that causes severe birth defects when taken during
the first trimester of pregnancy. The critical period for thalidomide-induced limb defects is between
days 20-36 of gestation. Teratogenesis refers to the production of birth defects in a developing embryo
or fetus.
Option B Rationale: Microcephaly is associated with Zika virus, maternal alcohol consumption, and
certain genetic conditions, but it is not the primary concern with thalidomide exposure. Thalidomide is
most notorious for causing phocomelia (limb defects).
Option C Rationale: Fetal alcohol spectrum disorders are caused by maternal alcohol consumption
during pregnancy, not thalidomide use. This option is incorrect for this scenario.
Option D Rationale: Cytomegalovirus is a congenital infection that can cause birth defects, but it is
unrelated to thalidomide exposure. This is not the correct concern for this client.
3. The nurse has attended a continuing education conference about genetic disorders. Which of the
following should the nurse list as autosomal recessive disorders?
Marfan syndrome
Polycystic kidney disease
,Cystic fibrosis
Phenylketonuria
Huntington's disease
Hemophilia A
A. 5,6
B. 3,4
C. 1,4
D. 2,6
ANSWER: B. 3,4
Rationale: Cystic fibrosis (3) and phenylketonuria (PKU) (4) are both autosomal recessive disorders.
Cystic fibrosis is caused by mutations in the CFTR gene on chromosome 7, while PKU is caused by
mutations in the PAH gene on chromosome 12. Both require two copies of the mutated gene (one from
each parent) for disease expression.
Option A Rationale: Huntington's disease (5) is an autosomal dominant disorder, and hemophilia A (6) is
an X-linked recessive disorder. Neither is autosomal recessive, making this combination incorrect.
Option C Rationale: Marfan syndrome (1) is an autosomal dominant disorder, not recessive. While PKU
(4) is correctly identified as autosomal recessive, the inclusion of Marfan syndrome makes this option
incorrect.
Option D Rationale: Polycystic kidney disease (2) has both autosomal dominant and autosomal recessive
forms, though the adult form is typically autosomal dominant. Hemophilia A (6) is X-linked recessive, not
autosomal recessive. This combination is incorrect.
, 4. A client asks the nurse about genetic testing for breast cancer. The nurse understands that which
genes are most commonly associated with hereditary breast and ovarian cancer syndrome?
A. BRCA1 and BRCA2
B. TP53 and PTEN
C. APC and MLH1
D. RET and VHL
ANSWER: A. BRCA1 and BRCA2
Rationale: BRCA1 and BRCA2 are tumor suppressor genes that, when mutated, significantly increase the
risk of breast and ovarian cancers. These are autosomal dominant genes with high penetrance. BRCA1 is
located on chromosome 17, and BRCA2 is on chromosome 13.
Option B Rationale: TP53 mutations cause Li-Fraumeni syndrome, which increases risk for multiple
cancers including breast cancer, but this is not the most common cause of hereditary breast cancer.
PTEN mutations cause Cowden syndrome, which is also associated with breast cancer but less
commonly than BRCA mutations.
Option C Rationale: APC mutations cause familial adenomatous polyposis (colon cancer risk), and MLH1
mutations cause Lynch syndrome (colorectal and other cancers). These are not primarily associated with
hereditary breast cancer.
Option D Rationale: RET mutations cause multiple endocrine neoplasia type 2, and VHL mutations cause
von Hippel-Lindau disease. Neither is primarily associated with hereditary breast cancer.
5. The nurse is caring for a newborn with phenylketonuria. Which dietary intervention should the nurse
anticipate teaching the parents?
A. Low-phenylalanine diet
B. High-protein diet
C. Gluten-free diet
and Genetic Disorders 2026!!
1. The nurse is caring for a client who has Huntington's disease. The nurse understands that this
autosomal dominant disorder affects which of the following organ systems?
A. Neurologic
B. Gastrointestinal
C. Muscular
D. Endocrine
ANSWER: A. Neurologic
Rationale: Huntington's disease is a progressive neurodegenerative disorder that primarily affects the
basal ganglia and cerebral cortex, leading to motor, cognitive, and psychiatric symptoms. It is caused by
a CAG trinucleotide repeat expansion in the HTT gene on chromosome 4.
Option B Rationale: While gastrointestinal symptoms such as dysphagia and weight loss can occur
secondary to neurologic impairment, the primary pathophysiology involves the nervous system, not the
gastrointestinal system itself.
Option C Rationale: Although choreiform movements and motor dysfunction are hallmark features,
these result from neurologic degeneration rather than primary muscular pathology. The muscles
themselves are structurally normal.
Option D Rationale: While some endocrine disturbances may occur secondary to hypothalamic
involvement, the primary disorder affects neurologic function, making this option incorrect.
,2. The nurse is interviewing a female client who is currently taking thalidomide and just learned they are
5 weeks pregnant. Which of the following should the nurse be concerned about?
A. Teratogenesis
B. Microcephaly
C. Fetal alcohol spectrum disorders
D. Cytomegalovirus
ANSWER: A. Teratogenesis
Rationale: Thalidomide is a well-known teratogen that causes severe birth defects when taken during
the first trimester of pregnancy. The critical period for thalidomide-induced limb defects is between
days 20-36 of gestation. Teratogenesis refers to the production of birth defects in a developing embryo
or fetus.
Option B Rationale: Microcephaly is associated with Zika virus, maternal alcohol consumption, and
certain genetic conditions, but it is not the primary concern with thalidomide exposure. Thalidomide is
most notorious for causing phocomelia (limb defects).
Option C Rationale: Fetal alcohol spectrum disorders are caused by maternal alcohol consumption
during pregnancy, not thalidomide use. This option is incorrect for this scenario.
Option D Rationale: Cytomegalovirus is a congenital infection that can cause birth defects, but it is
unrelated to thalidomide exposure. This is not the correct concern for this client.
3. The nurse has attended a continuing education conference about genetic disorders. Which of the
following should the nurse list as autosomal recessive disorders?
Marfan syndrome
Polycystic kidney disease
,Cystic fibrosis
Phenylketonuria
Huntington's disease
Hemophilia A
A. 5,6
B. 3,4
C. 1,4
D. 2,6
ANSWER: B. 3,4
Rationale: Cystic fibrosis (3) and phenylketonuria (PKU) (4) are both autosomal recessive disorders.
Cystic fibrosis is caused by mutations in the CFTR gene on chromosome 7, while PKU is caused by
mutations in the PAH gene on chromosome 12. Both require two copies of the mutated gene (one from
each parent) for disease expression.
Option A Rationale: Huntington's disease (5) is an autosomal dominant disorder, and hemophilia A (6) is
an X-linked recessive disorder. Neither is autosomal recessive, making this combination incorrect.
Option C Rationale: Marfan syndrome (1) is an autosomal dominant disorder, not recessive. While PKU
(4) is correctly identified as autosomal recessive, the inclusion of Marfan syndrome makes this option
incorrect.
Option D Rationale: Polycystic kidney disease (2) has both autosomal dominant and autosomal recessive
forms, though the adult form is typically autosomal dominant. Hemophilia A (6) is X-linked recessive, not
autosomal recessive. This combination is incorrect.
, 4. A client asks the nurse about genetic testing for breast cancer. The nurse understands that which
genes are most commonly associated with hereditary breast and ovarian cancer syndrome?
A. BRCA1 and BRCA2
B. TP53 and PTEN
C. APC and MLH1
D. RET and VHL
ANSWER: A. BRCA1 and BRCA2
Rationale: BRCA1 and BRCA2 are tumor suppressor genes that, when mutated, significantly increase the
risk of breast and ovarian cancers. These are autosomal dominant genes with high penetrance. BRCA1 is
located on chromosome 17, and BRCA2 is on chromosome 13.
Option B Rationale: TP53 mutations cause Li-Fraumeni syndrome, which increases risk for multiple
cancers including breast cancer, but this is not the most common cause of hereditary breast cancer.
PTEN mutations cause Cowden syndrome, which is also associated with breast cancer but less
commonly than BRCA mutations.
Option C Rationale: APC mutations cause familial adenomatous polyposis (colon cancer risk), and MLH1
mutations cause Lynch syndrome (colorectal and other cancers). These are not primarily associated with
hereditary breast cancer.
Option D Rationale: RET mutations cause multiple endocrine neoplasia type 2, and VHL mutations cause
von Hippel-Lindau disease. Neither is primarily associated with hereditary breast cancer.
5. The nurse is caring for a newborn with phenylketonuria. Which dietary intervention should the nurse
anticipate teaching the parents?
A. Low-phenylalanine diet
B. High-protein diet
C. Gluten-free diet
