ATI RN
Pediatrics Genetics Questions
Question 1 of 5
All are true about homeobox genes EXCEPT
Correct Answer: D
Rationale: Homeobox genes regulate development by determining tissue fate, acting as transcription factors, and controlling other genes. Mutations can cause aniridia (e.g., PAX6). However, tissues don’t typically revert to an undifferentiated state after homeobox gene action; their role is to direct differentiation, not reverse it.
Question 2 of 5
Karyotyping is not used in:
Correct Answer: C
Rationale: Karyotyping detects large chromosomal changes (deletions, inversions) but not small nucleotide insertions or point mutations, which require molecular techniques like sequencing.
Question 3 of 5
A chromosomal abnormality that involves 30 megabase region. The most likely abnormality to cause the worse disease is:
Correct Answer: A
Rationale: Deletion of a 30 Mb region removes many genes, likely causing severe disease (e.g., developmental delay). Duplications or inversions (pericentric/paracentric) may disrupt gene dosage or structure but are typically less severe than outright loss.
Question 4 of 5
You observed a patient with a genetic disorder for which there is no previous family history of his disease. which of the following scenarios could explain this situation:
Correct Answer: A
Rationale: No family history could result from a de novo mutation (new in the patient), germline mosaicism (parental gonadal mutation), anticipation (e.g., trinucleotide expansion), or reduced penetrance (hidden in prior generations). All are plausible.
Question 5 of 5
RET gene:
Correct Answer: D
Rationale: RET (proto-oncogene) gain-of-function mutations drive cancers (e.g., MEN2) via anti-apoptotic and proliferative effects. Loss of function causes Hirschsprung disease.