ATI RN
Common Pediatric Genetic Disorders Questions
Question 1 of 5
A 10-month-old baby with achondroplasia; developing recurrent apneas. Of the following, the MOST likely cause is
Correct Answer: B
Rationale: Achondroplasia causes foramen magnum stenosis (B), leading to brainstem compression and apnea. Rationale: Skeletal dysplasia narrows this passage; dental issues (A) or hydrocephalus (C) are less direct causes.
Question 2 of 5
Disorders caused by expansion of trinucleotide repeats include all the following EXCEPT
Correct Answer: B
Rationale: Ataxia-telangiectasia (B) is due to ATM mutations, not trinucleotide repeats. Rationale: Fragile X (A), Huntington (C), myotonic dystrophy (D), and Friedreich (E) involve CGG, CAG, CTG, GAA repeats.
Question 3 of 5
Consanguinity may increase the chance that a child will be born with a rare autosomal recessive (AR) condition. The risk of first cousins producing a child with an AR disorder is
Correct Answer: A
Rationale: First cousins share 1/8 genes; AR risk is 1/4 if both carriers, total ~1/16 (A). Rationale: General population risk is lower; consanguinity amplifies rare allele sharing.
Question 4 of 5
A 15-day-old baby with Down syndrome, during routine blood testing found to have high leukocyte count (34,000), the baby otherwise is asymptomatic. Of the following, the MOST appropriate advice /action is
Correct Answer: D
Rationale: Transient leukemoid reaction in DS newborns is common and benign (D). Rationale: Resolves spontaneously; leukemia (A) is a risk but not at 15 days without symptoms.
Question 5 of 5
Of the following, the one which carries the higher rate of congenital heart disease is
Correct Answer: C
Rationale: Down syndrome (C) has a ~50% CHD rate (e.g., AVSD). Rationale: Turner (A, ~30%), Williams (B, ~80% but rarer), and others (D, E) have lower or less frequent CHDs.