A 45-year-old mother gave birth to a baby boy two days ago. The ...

[Destiiny22]

A 45-year-old mother gave birth to a baby boy two days ago. The nurse assesses a single palmar crease, poor muscle tone, and low-set ears on the newborn.
 
  The nurse understands that these signs most likely indicate the infant has which autosomal abnormalities?
  1. Trisomy 13
  2. Trisomy 18
  3. Trisomy 21
  4. Trisomy 26

Question 2

The nurse has presented an in-service to nurses new to the maternalchild health care unit. Which statement indicates that teaching on genetic disorders has been successful?
 
  1. Down syndrome is an autosomal recessive condition. If both parents carry the gene, there is a 1-in-4 chance that a child will be affected.
  2. Galactosemia is a sex-linked condition. Both parents must carry the gene, and more girls than boys will be affected by this condition.
  3. Sickle-cell disease is a trisomy; the affected patient has three copies of a gene. Trisomies are more common in pregnancies of young women than those of older women.
  4. Huntington's disease is an autosomal dominant condition. Only one parent carries the gene, and males and females are equally affected by the disease.

[honnalora]

Answer to Question 1

Correct Answer: 3
Rationale 1: A single palmar crease and low-set ears are not characteristics of trisomy 13.
Rationale 2: A single palmar crease and low-set ears are not characteristics of trisomy 18.
Rationale 3: A single palmar crease and low-set ears are characteristics of trisomy 21 (Down syndrome).
Rationale 4: Trisomy 26 is not an autosomal abnormality.

Answer to Question 2

Correct Answer: 4
Rationale 1: Down syndrome is a trisomy and most likely to occur in parents over age 35. Autosomal recessive conditions are passed along to offspring when both parents carry the affected gene and pass the affected gene to the child.
Rationale 2: Galactosemia is not a sex-linked disorder; it is an autosomal recessive disorder. Both parents must carry the gene and pass that gene on to the child. Males and females are equally affected. Sex-linked disorders are carried on the X chromosome; therefore, males are more likely to have the condition because they only have one copy of the X chromosome.
Rationale 3: Trisomies are three copies of a specific gene and occur most often in parents over age 35. Sickle-cell disease is not a trisomy; it is an autosomal recessive condition. Both parents must carry the gene; there is a 1-in-4 chance that their child will be affected.
Rationale 4: Huntington's disease is an autosomal dominant disease, meaning that the affected person inherited the condition from only one affected parent. A child has a 50 chance of inheriting an autosomal dominant condition if one parent is affected. Males and females are equally affected by autosomal dominant disorders.