ATI RN
Pediatric Genetic Questions
Question 1 of 5
A medical student is asking about the meaning of balanced translocation in parents who have baby with Down syndrome. Of the following, the TRUE statement is
Correct Answer: A
Rationale: Balanced translocation (e.g., t(14;21)) means normal gene content, 45 chromosomes (A). Rationale: Carrier parents are phenotypically normal; unbalanced offspring get trisomy 21.
Question 2 of 5
Strictly speaking, maternal inheritance is best defined as
Correct Answer: D
Rationale: Maternal inheritance refers to traits passed via mitochondrial DNA, which is exclusively inherited from the mother since sperm contribute negligible mitochondria. X-linked recessive involves the X chromosome, not mitochondria, and sex-specific affliction isn’t accurate for mitochondrial inheritance.
Question 3 of 5
Genetic anticipation is best described as
Correct Answer: A
Rationale: Genetic anticipation occurs in trinucleotide repeat disorders, where repeat expansion increases severity or lowers onset age in subsequent generations (e.g., Huntington’s disease). It’s not a disorder, nor tied to sex-specific penetrance or imprinting.
Question 4 of 5
A newborn infant is noted to have dysmorphic features. The pregnancy was complicated by breech presentation, decreased fetal movements, and polyhydramnios. The child demonstrates hypotonia, a flat face, flattened occiput, epicanthal folds, and abdominal distention. The most likely cause of this child's dysmorphology is
Correct Answer: D
Rationale: Trisomy 21 (Down syndrome) matches these features: hypotonia, flat face, epicanthal folds, and polyhydramnios due to GI issues (e.g., duodenal atresia). Trisomy 13 and 18 (Edwards) have distinct, more severe anomalies. Trisomy 8 is rarer and less consistent with this presentation.
Question 5 of 5
Which of the following variants would you expect could to be most common:
Correct Answer: D
Rationale: C>T transitions are the most common DNA variants in humans, often due to deamination of cytosine to thymine, a frequent spontaneous mutation.