ATI RN
Genetic Pediatric Questions
Question 1 of 5
All the following are recognized associations in infant with Down syndrome EXCEPT
Correct Answer: D
Rationale: DS associations include polycythemia (A), leukemoid reaction (B), jaundice (C), and leukemia (E); cataracts (D) are less common neonatally. Rationale: Eye issues emerge later.
Question 2 of 5
The polymerase chain reaction is best described as
Correct Answer: B
Rationale: PCR amplifies DNA (or RNA via reverse transcription) to produce many copies from small samples. It’s not about antigenic epitopes or blotting techniques (Southern for DNA, Northern for RNA, Western for proteins).
Question 3 of 5
A 1-year-old presents with a disease that is classically an autosomal recessive trait (such as cystic fibrosis). The father is tested and, with 99% confidence, he is demonstrated to be negative for the carrier state. The most likely explanation is
Correct Answer: B
Rationale: If the father isn’t a carrier, the child could inherit two mutant alleles from the mother via uniparental isodisomy (both chromosomes from one parent). This explains an autosomal recessive trait without paternal contribution. Dominant mutation, paternal isodisomy, imprinting, or mitochondrial inheritance don’t fit.
Question 4 of 5
Which of the following DNA changes is pathogenic:
Correct Answer: D
Rationale: Mutations (sequence changes), epigenetic modifications (gene expression alterations), and variants (polymorphisms or mutations) can all be pathogenic depending on context—e.g., disrupting gene function or regulation.
Question 5 of 5
A European couple with diagnosis of hearing loss in father's brother in autosomal recessive variant. What is the probability to have an AFFECTED FETUS? Knowing that the carrier frequency of this variant in the European population is around 1/30.
Correct Answer: D
Rationale: Father’s brother affected means father has 2/3 chance of being a carrier (since parents are carriers). Mother’s carrier chance is 1/30 (population frequency). If both are carriers (2/3 × 1/30 = 2/90), child has 1/4 chance of being affected. Total = 2/90 × 1/4 = 1/180.