ATI RN
Pediatrics Genetics Questions
Question 1 of 5
Which of the following conditions shows anticipation in paternal transmission?
Correct Answer: D
Rationale: Fragile X syndrome shows anticipation (worsening with generations) via triplet repeat expansion, often more pronounced in paternal transmission.
Question 2 of 5
A 31-year-old man has a unilateral breast lump. A biopsy is performed, and the pathology report, surprisingly, shows an early-stage carcinoma. The man’s family history reveals no history of breast cancer. What would the physician be most likely to advise?
Correct Answer: B
Rationale: Male breast cancer suggests possible Klinefelter syndrome (47,XXY), warranting a karyotype to assess sex chromosomes.
Question 3 of 5
The figure below is the pedigree demonstrating the recurrence of Osteogenesis imperfecta in children with their father unaffected (arrow)
Correct Answer: A
Rationale: OI is AD. Unaffected father with affected kids suggests germline mosaicism; figure unavailable.
Question 4 of 5
Which P arm of the following chromosomes carries rDNA genes?
Correct Answer: B
Rationale: Chromosome 15’s p-arm carries ribosomal DNA (rDNA) genes, part of the nucleolar organizer regions (NORs) on acrocentric chromosomes (13, 14, 15, 21, 22). Answer 'B' is correct. Rationale: rDNA encodes ribosomal RNA, located in the short arms of these chromosomes, with 15 being a known carrier.
Question 5 of 5
A cell is in GO phase. How many chromosomes does it have?
Correct Answer: A
Rationale: G0 is a quiescent phase with no division; a human somatic cell has 46 chromosomes (A). Rationale: G0 cells are diploid (2n=46), not haploid (23) or replicated (92, G2 phase). Answer matches normal somatic count.