Nokea
Chromosome analysis of the fetus is usually accomplished through the testing of which?
- A. Fetal serum
- B. Maternal urine
- C. Amniotic fluid
- D. Maternal serum
Correct Answer: C
Rationale: Amniocentesis is the most common method to retrieve fetal cells for chromosome analysis. Viable fetal cells are sloughed off into the amniotic fluid, and when a sample is taken, they can be cultured and analyzed. It is difficult to obtain a sample of the fetal blood. It is a high-risk situation for the fetus. Fetal cells are not present in the maternal urine or blood.
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Which is a sex chromosome abnormality that is caused by the presence of one or more additional X chromosomes in a male?
- A. Turner
- B. Triple X
- C. Klinefelter
- D. Trisomy 13
Correct Answer: C
Rationale: Klinefelter syndrome is characterized by one or more additional X chromosomes. These individuals are tall with male secondary sexual characteristics that may be deficient, and they may be learning disabled. An absence of an X chromosome results in Turner syndrome. Triple X and trisomy 13 are not abnormalities that involve one or more additional X chromosomes in a male (Klinefelter syndrome).
Which is characteristic of X-linked recessive inheritance?
- A. There are no carriers.
- B. Affected individuals are principally males.
- C. Affected individuals are principally females.
- D. Affected individuals will always have affected parents.
Correct Answer: B
Rationale: In X-linked recessive disorders, the affected individuals are usually male. With recessive traits, usually two copies of the gene are needed to produce the effect. Because the male only has one X chromosome, the effect is visible with only one copy of the gene. Females are usually only carriers of X-linked recessive disorders. The X chromosome that does not have the recessive gene will produce the normal protein, so the woman will not show evidence of the disorder. The transmission is from mother to son. Usually the mother and father are unaffected.
The nurse is teaching parents of a child with cri du chat syndrome about this disorder. The nurse understands parents understand the teaching if they make which statement?
- A. This disorder is very common.
- B. This is an autosomal recessive disorder.
- C. The crying pattern is abnormal and catlike.
- D. The child will always have a moon-shaped face.
Correct Answer: C
Rationale: Typical of this disease is a crying pattern that is abnormal and catlike. Cri du chat, or cats cry, syndrome is a rare (one in 50,000 live births) chromosome deletion syndrome, not autosomal recessive, resulting from loss of the small arm of chromosome 5. In early infancy this syndrome manifests with a typical but nondistinctive facial appearance, often a moon-shaped face with wide-spaced eyes (hypertelorism). As the child grows, this feature is progressively diluted, and by age 2 years, the child is indistinguishable from age-matched control participants.
A couple expecting their first child has a positive family history for several congenital defects and disorders. The couple tells the nurse that they are opposed to abortion for religious reasons. Which should the nurse consider when counseling the couple?
- A. The couple should be encouraged to have recommended diagnostic testing.
- B. The couple needs counseling regarding advantages and disadvantages of pregnancy termination.
- C. Diagnostic testing is required by law in this situation.
- D. Diagnostic testing is of limited value if termination of pregnancy is not an option.
Correct Answer: A
Rationale: The benefits of prenatal diagnostic testing extend beyond decisions concerning abortion. If the child has congenital disorders, decisions can be made about fetal surgery if indicated. In addition, if the child is expected to require neonatal intensive care at birth, the mother is encouraged to deliver at a level III neonatal center. The couple is counseled about the advantages and disadvantages of prenatal diagnosis, not pregnancy termination, although the family cannot be forced to have prenatal testing. The information gives the parents time to grieve and plan for their child if congenital disorders are present. If the child is free of defects, then the parents are relieved of a major worry.
The nurse is reviewing a clients prenatal history. Which prescribed medication does the nurse understand is not considered a teratogen and prescribed during pregnancy?
- A. Phenytoin (Dilantin)
- B. Warfarin (Coumadin)
- C. Isotretinoin (Accutane)
- D. Heparin sodium (Heparin)
Correct Answer: D
Rationale: Teratogens, agents that cause birth defects when present in the prenatal environment, account for the majority of adverse intrauterine effects not attributable to genetic factors. Types of teratogens include drugs (phenytoin [Dilantin], warfarin [Coumadin], isotretinoin [Accutane]). Heparin is the anticoagulant used during pregnancy and is not a teratogen. It does not cross the placenta.