ATI RN
Genetic Disorders in Pediatrics Questions
Question 1 of 5
Possible causes of vaginal bleeding in a prepubertal female include all of the following EXCEPT
Correct Answer: C
Rationale: Bleeding causes include steroids (A), foreign bodies (B), urethral prolapse (D), and neoplasms (E). Hemorrhagic cystitis (C) causes urinary, not vaginal, bleeding. Rationale: Cystitis affects the bladder; vaginal bleeding requires a genital source.
Question 2 of 5
Neurofibromatosis Type 1 regarded as one of the most common AD disorders but many affected individuals have features so mild that they are never diagnosed. Of the following, the MOST likely cause of such phenomena is
Correct Answer: B
Rationale: Variable expressivity (B) explains mild NF1 phenotypes (e.g., few café-au-lait spots vs. tumors). Rationale: Penetrance (A) is near 100% in NF1; UPD (C) is unrelated.
Question 3 of 5
A 2-year-old girl with history of delayed speech, lonely play, and special hand movement (hand washing posture), the parents are healthy relative couple. The genetic cause of this disorder is MOST likely due to
Correct Answer: C
Rationale: Rett syndrome (hand-washing, regression) is often a de novo mutation (C) in MECP2 (XLD). Rationale: Healthy parents and consanguinity reduce carrier likelihood (A, B); not chromosomal (D).
Question 4 of 5
Fragile X syndrome (FRAX) is the most common cause of inherited intellectual disability. The individual who manifest the disease may have the number of trinucleotide repeat of CGG in the region Xq 27 of
Correct Answer: D
Rationale: Fragile X full mutation is >200 CGG repeat. Rationale: Normal is <45 (A), premutation 55–200 (B, C, D); >200 causes methylation and intellectual disability.
Question 5 of 5
Of the following, the study that is MOST useful in diagnosis of an aneuploidy is
Correct Answer: A
Rationale: Karyotyping (A) directly visualizes aneuploidy (e.g., trisomy 21). Rationale: FISH (B) confirms specific regions; microarray (C) detects microdeletions, not whole chromosome changes.