ATI RN
Pediatric Genetic Questions
Question 1 of 5
The shortest stage in cell cycle:
Correct Answer: A
Rationale: M phase (mitosis) is the shortest, typically 1–2 hours in a 24-hour cycle. 'A' is correct. Rationale: G1, S, and G2 (interphase) last longer (hours each), while GO is a quiescent state, not a timed phase. Mitosis is rapid, with visible stages like metaphase lasting minutes.
Question 2 of 5
Protects the DNA and prevents end-to-end fusion:
Correct Answer: A
Rationale: Telomeres (A) protect chromosome ends and prevent fusion. Rationale: TTAGGG repeats cap chromosomes, stabilizing them; centromeres attach spindles, subtelomeres are adjacent but not protective.
Question 3 of 5
CML is caused by:
Correct Answer: C
Rationale: Reciprocal t(9;22) (C) causes CML (Philadelphia chromosome). Rationale: BCR-ABL1 fusion drives myeloid proliferation; Robertsonian involves acrocentrics (e.g., 14;21), not 9;22.
Question 4 of 5
Baby with macrocephaly and severe intrauterine growth retardation:
Correct Answer: B
Rationale: Digynic (B, maternal triploidy) fits. Rationale: 2 maternal + 1 paternal sets (69, XXX/XXY) cause small fetus, macrocephaly; diandric has large placenta.
Question 5 of 5
Pathogenic mutations in TBX5 cause Holt-Oram syndrome which includes cardiovascular (atrial septal defect, hypoplastic left heart syndrome), chest (Absent pectoralis major muscle) and skeletal anomalies (vertebral anomalies, triphalangeal thumb and carpal bone anomalies). The TBX5 phenotypic effect is related to which concept:
Correct Answer: C
Rationale: Pleiotropy (C) describes one gene affecting multiple traits. TBX5 mutations cause diverse effects (heart, chest, skeleton), fitting this concept. Rationale: Unlike reduced penetrance (variable expression), sex-limited (gender-specific), or multifactorial (many factors), pleiotropy explains TBX5’s broad impact.