Chapter 6 Genetics and Genomics in Nursing
1. A baby is born with what the physician believes is a diagnosis of trisomy 21. This
means that the infant has three number 21 chromosomes. What factor describes the
etiology of this genetic change?
A) The mother also has genetic mutation of chromosome 21.
B) The patient has a nondisjunction occurring during meiosis. C) During
meiosis, a reduction of chromosomes resulted in 23. D) The patient will have a
single X chromosome and infertility. Ans: B
Feedback:
During meiosis, a pair of chromosomes may fail to separate completely, creating a
sperm or oocyte that contains either two copies or no copy of a particular
chromosome. This sporadic event, called nondisjunction, can lead to trisomy. Down
syndrome is an example of trisomy. The mother does not have a mutation of
chromosome 21, which is indicated in the question. Also, trisomy does not produce a
single X chromosome and infertility. Genes are packaged and arranged in a linear
order within chromosomes, which are located in the cell nucleus. In humans, 46
chromosomes occur in pairs in all body cells except oocytes and sperm, which contain
only 23 chromosomes.
2. The nurse reviews a patient's chart and notes that the patient has a gene mutation
that affects protein structure, producing hemoglobin S. The nurse knows that with
this gene mutation, the patient will experience symptoms of what?
A) Peripheral and pulmonary edema
B) Thrombotic organ damage
C) Metastasis of a glioblastoma D) Amyotrophic lateral sclerosis Ans: B
Feedback:
Sickle cell anemia is an example of a genetic condition caused by a small gene
mutation that affects protein structure, producing hemoglobin S. A person who
inherits two copies of the hemoglobin S gene mutation has sickle cell anemia and
experiences the symptoms of severe anemia and thrombotic organ damage resulting
in hypoxia. Amyotrophic lateral sclerosis is a neurodegenerative disease that can
occur as a result of an inherited mutation, but not a mutation of hemoglobin S. The
patient with sickle cell anemia may experience edema, but it would not be related to
the gene mutation. A glioblastoma is a neurologic tumor.
,3. During the admission assessment, the nurse notes many cafÈ-au-lait spots on the
patient's trunk, back, neck, and legs and suspects that the patient has
neurofibromatosis. Based on the nurse's knowledge of neurofibromatosis, the nurse
understands that a single family member has which of the following?
A) A spontaneous mutation
B) A germline mutation
C) A nondisjunction D) A monosomy Ans: A
Feedback:
Spontaneous mutations take place in individual oocytes or sperm at the time of
conception. These mutations are not inherited in other family members. However, a
person who carries the new ìspontaneousî mutation may pass on the mutation to his
or her children. Achondroplasia, Marfan syndrome, and neurofibromatosis type 1 are
examples of genetic conditions that may occur in a single family member as a result
of spontaneous mutation. Germline mutations are passed on to all daughter cells
when body cells replicate. During meiosis, a pair of chromosomes may fail to
separate completely, creating a sperm or oocyte that contains two copies or no copy
of a particular chromosome. This sporadic event, called nondisjunction, can lead to
either trisomy or a monosomy.
4. A 45-year-old man has just been diagnosed with Huntington disease. He and his wife
are concerned about their four children. What will the nurse understand about the
children's possibility of inheriting the gene for the disease?
A) Each child will have a 25% chance of inheriting the disease.
B) Each child will have a 50% chance of inheriting the disease. C) Each child will
have a 75% chance of inheriting the disease. D) Each child will have no chance of
inheriting the disease. Ans: B
Feedback:
Huntington disease is an autosomal dominant disorder. Autosomal dominant
inherited
conditions affect female and male family members equally and follow a vertical
pattern of inheritance in families. A person who has an autosomal dominant
inherited condition carries a gene mutation for that condition on one chromosome
pair. Each of that
person's offspring has a 50% chance of inheriting the gene mutation for the condition
, and a 50% chance of inheriting the normal version of the gene.
5. A young woman and her husband want to start a family. The young woman
explains to the nurse that she had a retinoblastoma as a child. The woman and her
husband are concerned about the chances of their son or daughter developing a
retinoblastoma. What is important for the nurse to explain to the couple?
A) Retinoblastoma is an autosomal recessive inheritance in which each
parent carries the gene mutation.
B) Retinoblastoma is an X-linked inheritance and all males inherit an X
chromosome from their mothers.
C) Retinoblastoma is an autosomal dominant inheritance that has
incomplete penetrance and can skip a generation.
D) Retinoblastoma is a pattern that is more horizontal than vertical; relatives
of a single generation tend to have the condition.
Ans: C
Feedback:
Retinoblastoma is an autosomal dominant inheritance that has incomplete
penetrance, and the gene appears to skip a generation, thus leading to errors in
interpreting family history and in genetic counseling. Autosomal recessive conditions
have a pattern that is more horizontal than vertical; relatives of a single generation
tend to have the
condition. Genetic conditions inherited in an autosomal recessive pattern are
frequently seen among particular ethnic groups and usually occur more often in
children of parents who are related by blood, such as first cousins. X-linked
conditions may be inherited in recessive or dominant patterns. In both, the gene
mutation is located on the X chromosome.
6. A 47-year-old patient with osteoarthritis and hypertension is diagnosed with breast
cancer. She tells the nurse that her mother also suffered from osteoarthritis and
hypertension, and she developed breast cancer at the age of 51 years. The nurse
1. A baby is born with what the physician believes is a diagnosis of trisomy 21. This
means that the infant has three number 21 chromosomes. What factor describes the
etiology of this genetic change?
A) The mother also has genetic mutation of chromosome 21.
B) The patient has a nondisjunction occurring during meiosis. C) During
meiosis, a reduction of chromosomes resulted in 23. D) The patient will have a
single X chromosome and infertility. Ans: B
Feedback:
During meiosis, a pair of chromosomes may fail to separate completely, creating a
sperm or oocyte that contains either two copies or no copy of a particular
chromosome. This sporadic event, called nondisjunction, can lead to trisomy. Down
syndrome is an example of trisomy. The mother does not have a mutation of
chromosome 21, which is indicated in the question. Also, trisomy does not produce a
single X chromosome and infertility. Genes are packaged and arranged in a linear
order within chromosomes, which are located in the cell nucleus. In humans, 46
chromosomes occur in pairs in all body cells except oocytes and sperm, which contain
only 23 chromosomes.
2. The nurse reviews a patient's chart and notes that the patient has a gene mutation
that affects protein structure, producing hemoglobin S. The nurse knows that with
this gene mutation, the patient will experience symptoms of what?
A) Peripheral and pulmonary edema
B) Thrombotic organ damage
C) Metastasis of a glioblastoma D) Amyotrophic lateral sclerosis Ans: B
Feedback:
Sickle cell anemia is an example of a genetic condition caused by a small gene
mutation that affects protein structure, producing hemoglobin S. A person who
inherits two copies of the hemoglobin S gene mutation has sickle cell anemia and
experiences the symptoms of severe anemia and thrombotic organ damage resulting
in hypoxia. Amyotrophic lateral sclerosis is a neurodegenerative disease that can
occur as a result of an inherited mutation, but not a mutation of hemoglobin S. The
patient with sickle cell anemia may experience edema, but it would not be related to
the gene mutation. A glioblastoma is a neurologic tumor.
,3. During the admission assessment, the nurse notes many cafÈ-au-lait spots on the
patient's trunk, back, neck, and legs and suspects that the patient has
neurofibromatosis. Based on the nurse's knowledge of neurofibromatosis, the nurse
understands that a single family member has which of the following?
A) A spontaneous mutation
B) A germline mutation
C) A nondisjunction D) A monosomy Ans: A
Feedback:
Spontaneous mutations take place in individual oocytes or sperm at the time of
conception. These mutations are not inherited in other family members. However, a
person who carries the new ìspontaneousî mutation may pass on the mutation to his
or her children. Achondroplasia, Marfan syndrome, and neurofibromatosis type 1 are
examples of genetic conditions that may occur in a single family member as a result
of spontaneous mutation. Germline mutations are passed on to all daughter cells
when body cells replicate. During meiosis, a pair of chromosomes may fail to
separate completely, creating a sperm or oocyte that contains two copies or no copy
of a particular chromosome. This sporadic event, called nondisjunction, can lead to
either trisomy or a monosomy.
4. A 45-year-old man has just been diagnosed with Huntington disease. He and his wife
are concerned about their four children. What will the nurse understand about the
children's possibility of inheriting the gene for the disease?
A) Each child will have a 25% chance of inheriting the disease.
B) Each child will have a 50% chance of inheriting the disease. C) Each child will
have a 75% chance of inheriting the disease. D) Each child will have no chance of
inheriting the disease. Ans: B
Feedback:
Huntington disease is an autosomal dominant disorder. Autosomal dominant
inherited
conditions affect female and male family members equally and follow a vertical
pattern of inheritance in families. A person who has an autosomal dominant
inherited condition carries a gene mutation for that condition on one chromosome
pair. Each of that
person's offspring has a 50% chance of inheriting the gene mutation for the condition
, and a 50% chance of inheriting the normal version of the gene.
5. A young woman and her husband want to start a family. The young woman
explains to the nurse that she had a retinoblastoma as a child. The woman and her
husband are concerned about the chances of their son or daughter developing a
retinoblastoma. What is important for the nurse to explain to the couple?
A) Retinoblastoma is an autosomal recessive inheritance in which each
parent carries the gene mutation.
B) Retinoblastoma is an X-linked inheritance and all males inherit an X
chromosome from their mothers.
C) Retinoblastoma is an autosomal dominant inheritance that has
incomplete penetrance and can skip a generation.
D) Retinoblastoma is a pattern that is more horizontal than vertical; relatives
of a single generation tend to have the condition.
Ans: C
Feedback:
Retinoblastoma is an autosomal dominant inheritance that has incomplete
penetrance, and the gene appears to skip a generation, thus leading to errors in
interpreting family history and in genetic counseling. Autosomal recessive conditions
have a pattern that is more horizontal than vertical; relatives of a single generation
tend to have the
condition. Genetic conditions inherited in an autosomal recessive pattern are
frequently seen among particular ethnic groups and usually occur more often in
children of parents who are related by blood, such as first cousins. X-linked
conditions may be inherited in recessive or dominant patterns. In both, the gene
mutation is located on the X chromosome.
6. A 47-year-old patient with osteoarthritis and hypertension is diagnosed with breast
cancer. She tells the nurse that her mother also suffered from osteoarthritis and
hypertension, and she developed breast cancer at the age of 51 years. The nurse
