ATI RN
Genetic Pediatric Questions
Question 1 of 5
Teratogenic agents are chemical, physical, or biologic agents that have the potential to damage embryonic tissue and result in congenital malformations. The rate of birth defects caused by teratogens is about
Correct Answer: B
Rationale: Teratogens cause ~6% of birth defects (B). Rationale: Most defects (~65%) are unknown etiology; genetic (~20%) and teratogens (~6%) are smaller fractions.
Question 2 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 3 of 5
A mentally retarded 15-year-old boy is found to have macroorchidism and large, prominent ears. He most likely has
Correct Answer: D
Rationale: Fragile X syndrome is characterized by intellectual disability, macroorchidism (enlarged testicles), and large ears, especially in males due to its X-linked inheritance. Cerebral giantism (Sotos syndrome) involves overgrowth but not typically macroorchidism. Acromegaly is a pituitary disorder seen in adults. Hypothyroidism doesn’t cause these features, and trisomy 21 (Down syndrome) presents with distinct facial features but not macroorchidism.
Question 4 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 5 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.