Final Chapter 10: Genetic Disorders & Prenatal Screening Flashcards
A nurse is educating a pregnant patient about the purpose of an ultrasound in the first trimester. Which statement by the patient indicates understanding?
A) “The ultrasound can determine my baby’s gender at this stage.”
B) “It will confirm the presence of a fetal heartbeat and gestational age.”
C) “This test will screen for gestational diabetes.”
D) “The ultrasound will check my cervix for dilation.”
B) “It will confirm the presence of a fetal heartbeat and gestational age.”
Rationale: First-trimester ultrasound confirms pregnancy, detects a fetal heartbeat, estimates gestational age, and rules out ectopic pregnancy. Fetal gender is typically determined after 16-20 weeks.
A patient at 32 weeks gestation is scheduled for a biophysical profile (BPP) via ultrasound. What does this test assess?
A) Placental maturity and fetal position
B) Fetal heart rate, movement, tone, breathing, and amniotic fluid volume
C) Cervical dilation and risk for preterm labor
D) The presence of fetal anomalies
B) Fetal heart rate, movement, tone, breathing, and amniotic fluid volume
Rationale: A biophysical profile (BPP) is a comprehensive fetal assessment that evaluates fetal well-being through ultrasound and a nonstress test (NST). A score of 8-10 is reassuring, while a low score indicates fetal distress.
A nurse is preparing a patient for a transabdominal ultrasound at 20 weeks gestation. What pre-procedure instruction should be given?
A) “Drink several glasses of water before the exam and do not urinate.”
B) “You need to empty your bladder completely before the test.”
C) “Avoid eating or drinking for 8 hours before the procedure.”
D) “This test requires an intravenous contrast injection.”
A) “Drink several glasses of water before the exam and do not urinate.”
Rationale: A full bladder improves visualization of pelvic structures during transabdominal ultrasound. In contrast, a transvaginal ultrasound requires an empty bladder.
A pregnant patient asks about the risks of ultrasound screening. Which response by the nurse is correct?
A) “Ultrasounds expose the baby to radiation, so they should be limited.”
B) “Ultrasounds may cause birth defects if done too frequently.”
C) “You will need sedation during the procedure.”
D) “Ultrasound is noninvasive and does not pose known risks to you or your baby.”
D) “Ultrasound is noninvasive and does not pose known risks to you or your baby.”
Rationale: Ultrasound uses sound waves (not radiation) and is considered safe during pregnancy. It does not cause birth defects and does not require sedation.
A patient is undergoing a nuchal translucency ultrasound at 12 weeks gestation. What condition is this test primarily screening for?
A) Spina bifida
B) Down syndrome and chromosomal abnormalities
C) Fetal lung maturity
D) Placental abruption
B) Down syndrome and chromosomal abnormalities
Rationale: Nuchal translucency ultrasound measures the fluid at the back of the fetal neck. Increased thickness may indicate trisomy 21 (Down syndrome) or other chromosomal abnormalities. It is typically performed between 11-14 weeks.
A nurse is assisting with a transvaginal ultrasound for a first-trimester patient. Which action is appropriate?
A) Ask the patient to empty their bladder before the procedure.
B) Ensure the patient has a full bladder for better visualization.
C) Position the patient in a prone position.
D) Place the ultrasound probe directly on the patient’s abdomen.
A) Ask the patient to empty their bladder before the procedure.
Rationale: Unlike transabdominal ultrasound, transvaginal ultrasound provides better visualization without a full bladder. The patient is positioned supine with knees bent.
A nurse is reviewing ultrasound results for a patient at 36 weeks gestation. Which finding is most concerning?
A) Amniotic fluid index (AFI) of 8 cm
B) Fetal heart rate of 140 bpm
C) Placenta previa covering the cervix
D) Fetal presentation in cephalic position
C) Placenta previa covering the cervix
Rationale: Placenta previa at 36 weeks increases the risk of hemorrhage and may require a C-section. The other findings are normal for a term pregnancy.
A 24-week pregnant patient is undergoing an ultrasound for fetal growth assessment. Which measurement is most commonly used?
A) Cervical length
B) Amniotic fluid index
C) Biparietal diameter and femur length
D) Endometrial thickness
C) Biparietal diameter and femur length
Rationale: Biparietal diameter (BPD), head circumference, femur length, and abdominal circumference are used to assess fetal growth and estimated gestational age in the second and third trimesters.
A nurse is explaining the doppler ultrasound portion of a biophysical profile (BPP). What is the purpose of this test?
A) To measure amniotic fluid levels
B) To assess fetal breathing movements
C) To evaluate blood flow through the umbilical cord and placenta
D) To determine fetal weight
C) To evaluate blood flow through the umbilical cord and placenta
Rationale: Doppler ultrasound assesses fetal circulation and placental function. It is commonly used in high-risk pregnancies (e.g., IUGR, preeclampsia).
A nurse is reviewing a patient’s ultrasound report at 28 weeks gestation. The amniotic fluid index (AFI) is 4 cm. What condition should the nurse suspect?
A) Oligohydramnios
B) Polyhydramnios
C) Normal findings
D) Hydatidiform mole
A) Oligohydramnios
Rationale: An AFI <5 cm indicates oligohydramnios, which is associated with fetal renal abnormalities, placental insufficiency, and fetal distress. Polyhydramnios is diagnosed if AFI > 25 cm.
What is the probability that an affected individual with an autosomal dominant disorder will pass the disorder on to their child?
A) 25%
B) 50%
C) 75%
D) 100%
B) 50%
Rationale: In autosomal dominant inheritance, an affected individual with one affected parent has a 50% chance of passing the disorder on to their child. This is because the affected parent has one dominant allele for the disorder, which can be transmitted to the offspring.
Which characteristics are true for autosomal dominant inheritance?(SATA)
A) Affected individuals always have two affected parents
B) Males and females are equally affected
C) The disorder can skip generations
D) The probability of passing the disorder is 50%
B) Males and females are equally affected
D) The probability of passing the disorder is 50%
Rationale: In autosomal dominant inheritance, males and females are equally affected, and an affected individual has a 50% chance of passing the disorder on to their offspring. It is not necessary for both parents to be affected, and the disorder generally does not skip generations.
Which nervous system disorder is commonly associated with autosomal dominant inheritance?
A) Cystic fibrosis
B) Sickle cell anemia
C) Phenylketonuria (PKU)
D) Huntington’s Disease
D) Huntington’s Disease
Rationale: Huntington’s Disease is a common autosomal dominant disorder affecting the nervous system, characterized by abnormal involuntary movements and progressive dementia.
What are the primary characteristics of polycystic kidney disease in autosomal dominant inheritance?
A) Small, functional cysts throughout the liver
B) Grape-like clusters of fluid-filled cysts in the kidney
C) Abnormal liver function
D) Increased cognitive function
B) Grape-like clusters of fluid-filled cysts in the kidney
Rationale: Polycystic kidney disease, an autosomal dominant disorder, is characterized by grape-like clusters of fluid-filled cysts in the kidney that replace functioning renal tissue, leading to renal impairment.
Which disorders are examples of autosomal dominant inheritance? (SATA)
A) Huntington’s Disease
B) Polycystic kidney disease
C) Cystic fibrosis
D) Tay-Sachs disease
A) Huntington’s Disease
B) Polycystic kidney disease
Rationale: Examples of autosomal dominant inheritance include Huntington’s Disease and polycystic kidney disease. Cystic fibrosis and Tay-Sachs disease are examples of autosomal recessive disorders.
How does autosomal dominant inheritance affect males and females?
A) Only males are affected
B) Only females are affected
C) Males and females are equally affected
D) It varies depending on environmental factors
C) Males and females are equally affected
Rationale: In autosomal dominant inheritance, both males and females are equally affected, as the disorder is inherited regardless of sex because the defective gene is located on an autosome (nonsex chromosome).
What is the main characteristic of autosomal dominant inheritance disorders?
A) Both alleles must be abnormal for the disorder to be expressed
B) The disorder skips generations
C) Only males are affected
D) A single gene in the heterozygous state is capable of producing the phenotype
D) A single gene in the heterozygous state is capable of producing the phenotype
Rationale: Autosomal dominant inheritance disorders occur when a single abnormal or mutant gene in the heterozygous state overshadows the normal gene, resulting in the expression of the disorder’s phenotype.
Which statements are true regarding autosomal dominant inheritance disorders?
A) The affected individual has a 50% chance of passing the abnormal gene to each child
B) Males and females are equally affected
C) The disorder can be passed from an affected male to his son
D) Phenotypically normal family members do not transmit the condition
all of the choices are correct
Rationale: In autosomal dominant inheritance, affected individuals have a 50% chance of passing the abnormal gene to each child. Males and females are equally affected, and an affected male can pass the disorder to his son. Phenotypically normal family members do not transmit the condition.
Why is male-to-male transmission important in distinguishing autosomal dominant inheritance from X-linked inheritance?
A) Because only autosomal recessive disorders show male-to-male transmission
B) Because autosomal dominant disorders do not affect females
C) Because X-linked inheritance does not exhibit male-to-male transmission
D) Because autosomal dominant disorders are inherited from the mother only
C) Because X-linked inheritance does not exhibit male-to-male transmission
Rationale: Male-to-male transmission is important in distinguishing autosomal dominant inheritance from X-linked inheritance because X-linked inheritance does not exhibit male-to-male transmission, as males inherit the X chromosome from their mothers.
What is the significance of varying degrees of presentation among individuals in a family with an autosomal dominant disorder?
A) It indicates that only some family members carry the gene
B) It means that all family members will have the same severity of the disorder
C) It means a parent with a mild form could have a child with a more severe form
D) It indicates the disorder is not inherited
C) It means a parent with a mild form could have a child with a more severe form
Rationale: Varying degrees of presentation among individuals in a family with an autosomal dominant disorder indicate that a parent with a mild form of the disorder could have a child with a more severe form, highlighting the variable expressivity of the disorder.
Which disorders follow an autosomal dominant pattern of inheritance?
A) Neurofibromatosis
B) Huntington disease
C) Achondroplasia
D) Polycystic kidney disease
all of the choices are correct
Rationale: Common genetic disorders that follow an autosomal dominant pattern of inheritance include neurofibromatosis, Huntington disease, achondroplasia, and polycystic kidney disease.
Which disorder is characterized by the growth of multiple, bilateral, grape-like clusters of fluid-filled cysts in the kidneys?
A) Huntington disease
B) Neurofibromatosis
C) Achondroplasia
D) Polycystic kidney disease
D) Polycystic kidney disease
Rationale: Polycystic kidney disease is characterized by the growth of multiple, bilateral, grape-like clusters of fluid-filled cysts in the kidneys that eventually compress and replace functioning renal tissue.
How is an autosomal dominant disorder inherited if one parent is affected?
A) There is a 25% chance the child will be affected
B) There is a 50% chance the child will be affected
C) There is a 75% chance the child will be affected
D) The disorder skips a generation
B) There is a 50% chance the child will be affected
Rationale: If one parent is affected by an autosomal dominant disorder, there is a 50% chance that the child will inherit the abnormal gene and be affected by the disorder.
What type of genetic disorder is Huntington disease?
A) Autosomal recessive
B) X-linked dominant
C) Autosomal dominant
D) Mitochondrial
C) Autosomal dominant
Rationale: Huntington disease is an autosomal dominant genetic disorder that affects the nervous system, characterized by abnormal involuntary movements and progressive dementia.