ATI RN
Genetic Disorders in Pediatrics Questions
Question 1 of 5
Which of the following is a feature of X-linked dominant inheritance?
Correct Answer: C
Rationale: X-linked dominant traits show no male-to-male transmission (fathers pass X to daughters only), but ‘transmission only by females’ is inaccurate; males transmit to daughters.
Question 2 of 5
Which of the following is not a chromosome instability syndrome?
Correct Answer: A
Rationale: Klinefelter (47,XXY) is an aneuploidy, not a chromosome instability syndrome (e.g., DNA repair defects).
Question 3 of 5
The most common cystic fibrosis mutation consists of:
Correct Answer: A
Rationale: The most common CF mutation is ΔF508, a 3-base-pair deletion in CFTR.
Question 4 of 5
If both parents are affected with the same autosomal recessive disorder then the probability that each of their children will be affected equals
Correct Answer: D
Rationale: If both parents are homozygous recessive (aa x aa), all offspring will be aa (100% affected).
Question 5 of 5
A full-term female newborn is examined shortly after birth. She appears to be small for gestational age, and she has excess skin on the nape of the neck and lymphedema of the hands and feet. Chromosomal analysis shows some cells with a normal 46,XY karyotype and some cells with a 45,X karyotype. Which of the following mechanisms best explains this cytogenetic abnormality?
Correct Answer: A
Rationale: Mosaicism (46,XY/45,X) arises from mitotic nondisjunction post-fertilization, losing an X or Y in some cells.