ATI RN
Common Pediatric Genetic Disorders Questions
Question 1 of 5
Of the following, the one which carries the higher rate of congenital heart disease is
Correct Answer: C
Rationale: Down syndrome (C) has a ~50% CHD rate (e.g., AVSD). Rationale: Turner (A, ~30%), Williams (B, ~80% but rarer), and others (D, E) have lower or less frequent CHDs.
Question 2 of 5
The most important reason to carefully screen for Y chromosome material in patients with Turner syndrome is to
Correct Answer: D
Rationale: Y chromosome material in Turner syndrome (e.g., 45,X/46,XY mosaicism) increases gonadoblastoma risk, a potentially malignant tumor. This is the primary screening reason, not masculinization, contraception, androgen therapy, or prostate cancer (which requires a prostate).
Question 3 of 5
Individual A is affected with hearing loss (HL) and his ethnic background is African. Individual E is also affected with HL and his ethnic background is European:
Correct Answer: D
Rationale: Genomic similarity is higher within ethnic groups due to shared ancestry. Individual A (African) is more similar to another unaffected African than to Individual E (European), despite shared HL, which may have different genetic causes.
Question 4 of 5
The percentage of DNA sequence variation between humans is the lowest in:
Correct Answer: D
Rationale: Exons (coding regions) have the lowest variation between humans (~0.1%) due to evolutionary conservation of protein function. Non-coding regions (repeats, introns, transposable elements) tolerate more variation.
Question 5 of 5
A 6-month-old with unilateral retinoblastoma has genetic testing performed. The results of the tumor and blood analysis at the RBI locus are shown below. What is the likelihood that a future sibling WILL NOT DEVELOP retinoblastoma? (R is Arginine and X is stop codon)
Correct Answer: B
Rationale: Unilateral retinoblastoma without family history is often sporadic (non-heritable), with two somatic hits in the tumor. Blood normal (no germline mutation) means siblings have population risk (<1/20,000), approximated as >99% chance of not developing it.