ATI RN
Genetic Pediatric Questions
Question 1 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 2 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 3 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.
Question 4 of 5
A patient with retinoblastoma has a single tumor in one eye; the other eye is free of tumors:
Correct Answer: D
Rationale: Unilateral, single-tumor retinoblastoma is typically sporadic (two somatic hits), not heritable (which often presents bilaterally or multifocally). Parents are unaffected in sporadic cases.
Question 5 of 5
A gain of abnormal function rather than excessive activity in an oncogene could most probably occur through:
Correct Answer: A
Rationale: A point mutation in an exon can alter protein function (e.g., RAS mutations), causing abnormal activity, unlike promoter mutations or amplification, which increase expression.