MIDTERM CH 10: Genetic Disorders and Prenatal Screening Flashcards
Which of the following characteristics is specific to autosomal dominant inheritance?
A. Only females are affected, and male-to-male transmission does not occur.
B. The condition skips generations in families.
C. Only males are affected, and they cannot transmit the disorder to their sons.
D. An affected individual has a 50% chance of passing the abnormal gene to offspring.
D. An affected individual has a 50% chance of passing the abnormal gene to offspring.
Rationale: In autosomal dominant inheritance, an affected person has a 50% chance of passing the abnormal gene to each child, regardless of the child’s sex. This type of inheritance does not skip generations, and both males and females are equally affected. Male-to-male transmission is a key feature distinguishing autosomal dominant inheritance from X-linked inheritance.
A family is being counseled about Huntington disease, which follows an autosomal dominant inheritance pattern. The father is affected by the disease, but the mother is unaffected. What is the probability of their child inheriting Huntington disease?
A. 0%
B. 25%
C. 50%
D. 75%
C. 50%
Rationale: In autosomal dominant inheritance, each child of an affected parent has a 50% chance of inheriting the abnormal gene. This probability is independent for each pregnancy and does not depend on the sex of the child.
Which statement about autosomal dominant disorders indicates a need for further teaching?
A. “A person with the disorder may have a more severe form than their parent.”
B. “Males cannot pass autosomal dominant disorders to their sons.”
C. “An affected person typically has one affected parent.”
D. “The condition is equally likely to affect males and females.”
B. “Males cannot pass autosomal dominant disorders to their sons.”
Rationale: Male-to-male transmission is possible in autosomal dominant inheritance because the disorder is not linked to sex chromosomes. This distinguishes autosomal dominant inheritance from X-linked inheritance.
A couple is asking about the risk of neurofibromatosis, an autosomal dominant condition, in their children. The father is affected, and the mother is not. What information should the nurse provide?
A. “Each child has a 25% chance of inheriting the condition.”
B. “Each child has a 50% chance of inheriting the condition.”
C. “Only male children are at risk for inheriting the condition.”
D. “The condition typically skips generations in families.”
B. “Each child has a 50% chance of inheriting the condition.”
Rationale: In autosomal dominant conditions, each child of an affected parent has a 50% chance of inheriting the abnormal gene, regardless of the child’s sex. The condition does not skip generations.
Which of the following features distinguishes autosomal dominant inheritance from X-linked inheritance?
A. Male-to-male transmission occurs in autosomal dominant inheritance.
B. Autosomal dominant inheritance affects only males.
C. Autosomal dominant inheritance skips generations.
D. Male carriers of autosomal dominant disorders do not pass the condition to their offspring.
A. Male-to-male transmission occurs in autosomal dominant inheritance.
Rationale: Male-to-male transmission is a hallmark of autosomal dominant inheritance, distinguishing it from X-linked inheritance, where male-to-male transmission does not occur. Autosomal dominant inheritance does not skip generations and affects both sexes equally.
A parent with achondroplasia, an autosomal dominant condition, expresses concern about the severity of the condition in their children. What information should the nurse provide?
A. “The severity of the condition is the same in all individuals.”
B. “A child may have a more severe form of the condition than the parent.”
C. “The condition will not affect females if inherited from the father.”
D. “If a child inherits the gene, the condition will be milder than in the parent.”
B. “A child may have a more severe form of the condition than the parent.”
Which of the following genetic inheritance patterns is characteristic of autosomal recessive disorders?
A. Two abnormal genes are necessary to express the disorder.
B. Only one abnormal gene is needed to express the disorder.
C. Males are more affected than females due to X-linked inheritance.
D. Affected individuals are present in every generation of the family.
A. Two abnormal genes are necessary to express the disorder.
Rationale: Autosomal recessive inheritance requires two copies of the mutant gene (one from each parent) for the individual to express the disorder. This differs from autosomal dominant disorders and X-linked inheritance. Unlike dominant disorders, autosomal recessive disorders typically affect one generation and do not appear in every generation.
Which of the following statements about autosomal recessive inheritance indicates a need for further teaching?
A. “If both parents are carriers, their child has a 25% chance of being affected.”
B. “Carriers of the disorder may pass the abnormal gene to their offspring.”
C. “Males are more likely to be affected than females.”
D. “Consanguinity increases the chance of both parents being carriers.”
C. “Males are more likely to be affected than females.”
Rationale: Autosomal recessive disorders affect males and females equally because the inheritance is not linked to the sex chromosomes. A 25% chance of being affected (A), the potential for carriers to pass the gene (B), and the impact of consanguinity (D) are all accurate aspects of autosomal recessive inheritance.
A couple, both carriers for cystic fibrosis, ask about the chances of passing the condition to their child. Which response by the nurse is correct?
A. “There is a 50% chance your child will inherit two abnormal genes and develop the condition.”
B. “There is a 25% chance your child will inherit two abnormal genes and develop the condition.”
C. “Your child has a 50% chance of inheriting one abnormal gene and being affected.”
D. “Your child cannot inherit the condition unless both parents are affected.”
B. “There is a 25% chance your child will inherit two abnormal genes and develop the condition.”
Rationale: In autosomal recessive inheritance, when both parents are carriers, there is a 25% chance the child will inherit two abnormal genes and express the condition, a 50% chance of being a carrier, and a 25% chance of inheriting no abnormal genes.
Which of the following conditions is an example of an autosomal recessive disorder?
A. Huntington disease
B. Neurofibromatosis
C. Tay–Sachs disease
D. Marfan syndrome
C. Tay–Sachs disease
Rationale: Tay–Sachs disease is an autosomal recessive disorder requiring two copies of the mutant gene for expression. Huntington disease (A), neurofibromatosis (B), and Marfan syndrome (D) are autosomal dominant conditions.
A family has one child with sickle cell disease and is planning to have another child. Both parents are carriers. Which of the following statements should the nurse include when discussing the inheritance pattern? (Select all that apply)
A. “Each pregnancy has a 25% chance of the child having sickle cell disease.”
B. “Each pregnancy has a 50% chance of the child being a carrier.”
C. “Each pregnancy has a 50% chance of the child having sickle cell disease.”
D. “Each pregnancy has a 25% chance of the child being unaffected.”
E. “Sickle cell disease affects males and females equally.”
A. “Each pregnancy has a 25% chance of the child having sickle cell disease.”
B. “Each pregnancy has a 50% chance of the child being a carrier.”
D. “Each pregnancy has a 25% chance of the child being unaffected.”
E. “Sickle cell disease affects males and females equally.”
Rationale: In autosomal recessive inheritance, each pregnancy has a 25% chance of the child inheriting two abnormal genes and having the disorder (A), a 50% chance of being a carrier (B), and a 25% chance of being unaffected (D). Since the inheritance is not sex-linked, males and females are equally affected (E).
Which of the following is a primary purpose of genetic counseling?
A. Diagnosing and treating genetic diseases in clients and families.
B. Reducing pregnancy risks and establishing early prenatal care.
C. Providing genetic testing to all pregnant women regardless of their history.
D. Identifying and communicating genetic risks to families.
D. Identifying and communicating genetic risks to families.
Rationale: Genetic counseling aims to provide families with information about genetic risks, including potential conditions and management options. While reducing pregnancy risks (B) and prenatal care are part of preconception counseling, genetic counseling extends beyond this to include evaluation and support for genetic conditions.
The nurse is explaining genetic counseling to a client who is planning a pregnancy. Which statement by the nurse requires correction?
A. “Genetic counseling only applies to individuals with a family history of genetic disorders.”
B. “Genetic counseling can confirm, diagnose, or rule out a genetic condition.”
C. “It is ideal to have genetic counseling before conception occurs.”
D. “A detailed family history and pedigree are important parts of genetic counseling.”
A. “Genetic counseling only applies to individuals with a family history of genetic disorders.”
Rationale: Genetic counseling is not limited to individuals with a family history of genetic disorders. It may also be beneficial for couples planning a family, those with a history of congenital anomalies, or suspected teratogen exposure.
Which scenario would most likely require urgent genetic counseling?
A. A couple planning their first pregnancy with a history of teratogen exposure.
B. A child diagnosed prenatally with a life-threatening genetic disease.
C. A family history of a genetic disorder in a couple planning to conceive.
D. A diagnosis of a genetic disorder in a client’s extended family.
B. A child diagnosed prenatally with a life-threatening genetic disease.
Rationale: Urgent genetic counseling is needed in situations where immediate decisions, such as continuation or termination of pregnancy, must be made due to the diagnosis of a life-threatening condition.
When gathering a family history for genetic counseling, which action is most appropriate?
A. Limiting the history to immediate family members only.
B. Requesting medical records only for family members currently alive.
C. Informing families in advance about the need for detailed and sensitive information.
D. Gathering information only for individuals who have genetic disorders.
C. Informing families in advance about the need for detailed and sensitive information.
Rationale: Informing families about the need for detailed information allows them time to collect necessary facts and prepare for sensitive discussions. A detailed family history typically includes three generations and may require information beyond immediate family members.
Which of the following is an ethical consideration in genetic counseling?
A. Recommending termination of a pregnancy when a genetic disorder is identified.
B. Avoiding discussions about disorders that have no prenatal screening tests available.
C. Encouraging genetic testing for all couples regardless of their preferences.
D. Maintaining client autonomy by presenting information nonjudgmentally.
D. Maintaining client autonomy by presenting information nonjudgmentally.
Rationale: A key ethical principle in genetic counseling is respecting client autonomy and presenting information in a nonjudgmental and nondirective manner, allowing clients to make informed decisions based on their values.
What is the most appropriate time for genetic counseling?
A. During the second trimester of pregnancy.
B. At the time of delivery to prepare for newborn care.
C. Before conception occurs.
D. Only when a genetic disorder is diagnosed in the family.
C. Before conception occurs.
Rationale: The ideal time for genetic counseling is before conception, allowing couples to plan for potential risks and establish prenatal care early.
Which of the following statements about the role of genetic counselors is true?
A. They analyze genetic data and communicate risks to families.
B. They determine whether a couple should proceed with a pregnancy.
C. They are primarily responsible for treating genetic disorders.
D. They only work with families who have existing genetic conditions.
A. They analyze genetic data and communicate risks to families.
Rationale: Genetic counselors are responsible for evaluating genetic risks, providing education, and offering support to families. They do not make decisions for the clients or focus solely on families with pre-existing conditions.
A client considering genetic counseling expresses concern about privacy. Which response by the nurse is most appropriate?
A. “Your privacy is guaranteed, and no information will be shared under any circumstances.”
B. “Confidentiality will be maintained, but sensitive information may emerge that requires discussion.”
C. “You should not worry about privacy because this process is routine for all families.”
D. “We will share the genetic results with other family members to help them prepare.”
B. “Confidentiality will be maintained, but sensitive information may emerge that requires discussion.”
Rationale: While confidentiality is critical in genetic counseling, clients should be aware that sensitive information (e.g., unknown parentage or adoption) may be revealed during the process.
What is an important nursing consideration when providing genetic counseling to a client from a culturally diverse background?
A. Recommending genetic testing based on the nurse’s understanding of their cultural risks.
B. Providing standardized genetic information regardless of cultural differences.
C. Maintaining sensitivity to cultural values while presenting information nondirectively.
D. Avoiding discussions about genetic conditions that may conflict with cultural beliefs.
C. Maintaining sensitivity to cultural values while presenting information nondirectively.
Rationale: Nurses must respect cultural values and beliefs while providing genetic counseling in a nondirective and culturally sensitive manner, ensuring the client feels supported in their decision-making process.
What is the purpose of combining first-trimester screening with second-trimester (quad screen) for women under 35?
A. To determine the exact genetic disorder affecting the fetus.
B. To improve detection rates of chromosomal abnormalities.
C. To eliminate the need for cell-free DNA testing.
D. To detect neural tube defects only.
B. To improve detection rates of chromosomal abnormalities
Rationale: Combining first-trimester and second-trimester screenings increases the accuracy of detecting chromosomal abnormalities such as Down syndrome.
Which components are included in a nuchal translucency screening?
A. Blood markers and assessment of the nasal bone.
B. Measurement of fetal fraction of DNA and nasal bone presence.
C. Cell-free DNA testing and second-trimester ultrasound.
D. MSAFP alone.
A. Blood markers and assessment of the nasal bone.
Rationale: Nuchal translucency screening combines blood markers with ultrasound findings, such as the presence or absence of the nasal bone, to assess the risk of chromosomal abnormalities.
Why are MSAFP or quad screen results less accurate when used alone compared to combined screening?
A. They lack the genetic component of fetal fraction DNA.
B. They do not account for first-trimester markers.
C. They are performed at the wrong gestational age.
D. They primarily detect maternal health issues.
B. They do not account for first-trimester markers.
Rationale: When used alone, these tests lack the complementary data provided by first-trimester markers, reducing their overall accuracy.
What does the “time-sensitive” label refer to in genetic screening?
A. The need for results before labor begins.
B. The urgency of counseling after abnormal findings.
C. The delay in results due to genetic analysis.
D. The requirement for screening within specific gestational windows.
D. The requirement for screening within specific gestational windows.
Rationale: Genetic screening tests must be performed at specific gestational ages to ensure accurate results, as fetal development changes rapidly.
