ATI RN
Pediatric Genetic Disorders Questions
Question 1 of 4
To evaluate abdominal distention, a KUB reveals a 'double bubble' sign. The best explanation for the neonate's abdominal distention is
Correct Answer: D
Rationale: The ‘double bubble’ sign on KUB indicates duodenal atresia, common in Down syndrome, causing a gas bubble in the stomach and proximal duodenum. Hirschsprung, meconium ileus, and plugs cause distal obstructions. Pyloric atresia is rarer and doesn’t produce this sign.
Question 2 of 4
This is an electrophoresis (southern blots) for an individual with hereditary retinoblastoma; both normal and tumor cells were genotyped for three polymorphic markers flanking the RBI locus on chromosome 13 for this patient (N=normal cells, T=tumor cells). Based on the figure, which of the following is the most likely to explain the genetic mutation in this patient's cancer?
Correct Answer: A
Rationale: Hereditary retinoblastoma involves one germline RB1 mutation. Tumorigenesis requires a second hit (Knudson’s two-hit hypothesis). Southern blot showing loss of normal allele in tumor cells suggests a second somatic mutation, not chromosome loss.
Question 3 of 4
Which of the following is NOT a familial cancer syndrome:
Correct Answer: C
Rationale: Waardenburg syndrome causes pigmentation/hearing issues, not cancer. Others (Li-Fraumeni, NF2, FAP) are cancer syndromes.
Question 4 of 4
Next Generation Sequencing (NGS) can perform Whole Exome Sequencing (WES) for the entire coding regions in one reaction. WES will be more successful in detecting a candidate disease-causing change in:
Correct Answer: D
Rationale: WES targets exons (coding regions) and is best at detecting synonymous splicing variants (affecting splice sites within exons). Promoters, enhancers, and imprinting are outside exonic focus.