Genetics, Conception, and Fetal Development Perry:
Maternal Child Nursing Care, 6th Edition
1. A father and mother are carriers of phenylketonuria (PKU). Their 2-year-old daughter has PKU. The
couple tells the nurse that they are planning to have a second baby. Because their daughter has PKU,
they are sure that their next baby won't be affected. What response by the nurse is most accurate?
a. "Good planning; you need to take advantage of the odds in your favor."
b. "I think you'd better check with your doctor first."
c. "You are both carriers, so each baby has a 25% chance of being affected."
d. "The ultrasound indicates a boy, and boys are not affected by PKU." - ANS: C
The chance is one in four that each child produced by this couple will be affected by PKU disorder. This
couple still has an increased likelihood of having a child with PKU. Having one child already with PKU
does not guarantee that they will not have another. These parents need to discuss their options with
their physician. However, an opportune time has presented itself for the couple to receive correct
teaching about inherited genetic risks. No correlation exists between gender and inheritance of the
disorder because PKU is an autosomal recessive disorder.
2. The nurse is providing genetic counseling for an expectant couple who already have a child with
trisomy 18. The nurse should:
a. tell the couple they need to have an abortion within 2 to 3 weeks.
b. explain that the fetus has a 50% chance of having the disorder.
c. discuss options with the couple, including amniocentesis to determine whether the fetus is affected.
d. refer the couple to a psychologist for emotional support. - ANS: C
Genetic testing, including amniocentesis, would need to be performed to determine whether the fetus is
affected. The couple should be given information about the likelihood of having another baby with this
disorder so that they can make an informed decision. A genetic counselor is the best source for
determining genetic probability ratios. The couple eventually may need emotional support, but the
status of the pregnancy must be determined first.
3. The nurse is assessing the knowledge of new parents with a child born with maple syrup urine
disease (MSUD). This is an autosomal recessive inherited disorder, which means that:
a. both genes of a pair must be abnormal for the disorder to be expressed.
, b. only one copy of the abnormal gene is required for the disorder to be expressed.
c. the disorder occurs in males and heterozygous females.
d. the disorder is carried on the X chromosome. - ANS: A
MSUD is a type of autosomal recessive inheritance disorder in which both genes of a pair must be
abnormal for the disorder to be expressed. MSUD is not an X-linked dominant or recessive disorder or
an autosomal dominant inheritance disorder.
4. In presenting to obstetric nurses interested in genetics, the genetic nurse identifies the primary risk(s)
associated with genetic testing as:
a. anxiety and altered family relationships.
b. denial of insurance benefits.
c. high false-positive results associated with genetic testing.
d. ethnic and socioeconomic disparity associated with genetic testing. - ANS: B
Decisions about genetic testing are shaped by socioeconomic status and the ability to pay for the
testing. Some types of genetic testing are expensive and are not covered by insurance benefits. Anxiety
and altered family relationships, high false-positive results, and ethnic and socioeconomic disparity are
factors that may be difficulties associated with genetic testing, but they are not risks associated with
testing.
5. A man's wife is pregnant for the third time. One child was born with cystic fibrosis, and the other
child is healthy. The man wonders what the chance is that this child will have cystic fibrosis. This type of
testing is known as:
a. occurrence risk.
b. recurrence risk.
c. predictive testing.
d. predisposition testing. - ANS: B
The couple already has a child with a genetic disease so they will be given a recurrence risk test. If a
couple has not yet had children but are known to be at risk for having children with a genetic disease,
they are given an occurrence risk test. Predictive testing is used to clarify the genetic status of an
asymptomatic family member. Predisposition testing differs from presymptomatic testing in that a
positive result does not indicate 100% risk of a condition developing.
6. A key finding from the Human Genome Project is:
Maternal Child Nursing Care, 6th Edition
1. A father and mother are carriers of phenylketonuria (PKU). Their 2-year-old daughter has PKU. The
couple tells the nurse that they are planning to have a second baby. Because their daughter has PKU,
they are sure that their next baby won't be affected. What response by the nurse is most accurate?
a. "Good planning; you need to take advantage of the odds in your favor."
b. "I think you'd better check with your doctor first."
c. "You are both carriers, so each baby has a 25% chance of being affected."
d. "The ultrasound indicates a boy, and boys are not affected by PKU." - ANS: C
The chance is one in four that each child produced by this couple will be affected by PKU disorder. This
couple still has an increased likelihood of having a child with PKU. Having one child already with PKU
does not guarantee that they will not have another. These parents need to discuss their options with
their physician. However, an opportune time has presented itself for the couple to receive correct
teaching about inherited genetic risks. No correlation exists between gender and inheritance of the
disorder because PKU is an autosomal recessive disorder.
2. The nurse is providing genetic counseling for an expectant couple who already have a child with
trisomy 18. The nurse should:
a. tell the couple they need to have an abortion within 2 to 3 weeks.
b. explain that the fetus has a 50% chance of having the disorder.
c. discuss options with the couple, including amniocentesis to determine whether the fetus is affected.
d. refer the couple to a psychologist for emotional support. - ANS: C
Genetic testing, including amniocentesis, would need to be performed to determine whether the fetus is
affected. The couple should be given information about the likelihood of having another baby with this
disorder so that they can make an informed decision. A genetic counselor is the best source for
determining genetic probability ratios. The couple eventually may need emotional support, but the
status of the pregnancy must be determined first.
3. The nurse is assessing the knowledge of new parents with a child born with maple syrup urine
disease (MSUD). This is an autosomal recessive inherited disorder, which means that:
a. both genes of a pair must be abnormal for the disorder to be expressed.
, b. only one copy of the abnormal gene is required for the disorder to be expressed.
c. the disorder occurs in males and heterozygous females.
d. the disorder is carried on the X chromosome. - ANS: A
MSUD is a type of autosomal recessive inheritance disorder in which both genes of a pair must be
abnormal for the disorder to be expressed. MSUD is not an X-linked dominant or recessive disorder or
an autosomal dominant inheritance disorder.
4. In presenting to obstetric nurses interested in genetics, the genetic nurse identifies the primary risk(s)
associated with genetic testing as:
a. anxiety and altered family relationships.
b. denial of insurance benefits.
c. high false-positive results associated with genetic testing.
d. ethnic and socioeconomic disparity associated with genetic testing. - ANS: B
Decisions about genetic testing are shaped by socioeconomic status and the ability to pay for the
testing. Some types of genetic testing are expensive and are not covered by insurance benefits. Anxiety
and altered family relationships, high false-positive results, and ethnic and socioeconomic disparity are
factors that may be difficulties associated with genetic testing, but they are not risks associated with
testing.
5. A man's wife is pregnant for the third time. One child was born with cystic fibrosis, and the other
child is healthy. The man wonders what the chance is that this child will have cystic fibrosis. This type of
testing is known as:
a. occurrence risk.
b. recurrence risk.
c. predictive testing.
d. predisposition testing. - ANS: B
The couple already has a child with a genetic disease so they will be given a recurrence risk test. If a
couple has not yet had children but are known to be at risk for having children with a genetic disease,
they are given an occurrence risk test. Predictive testing is used to clarify the genetic status of an
asymptomatic family member. Predisposition testing differs from presymptomatic testing in that a
positive result does not indicate 100% risk of a condition developing.
6. A key finding from the Human Genome Project is:
