ATI RN
Genetic Disorders in Pediatrics Questions
Question 1 of 5
Suppose there’s an X-linked recessive disease, if the mother has the disease, while the father doesn’t, what’s the chance that they’ll have an affected female?
Correct Answer: D
Rationale: Zero (D) chance for an affected female. Rationale: Mother (XX, affected, X^a X^a) and father (XY, unaffected, X^+ Y) produce sons (X^a Y, all affected) and daughters (X^a X^+, carriers). X-linked recessive requires two mutant alleles in females, impossible here.
Question 2 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 3 of 5
Maternal exposure to DES places the female offspring at increased risk for
Correct Answer: B
Rationale: DES exposure in utero increases risk of clear cell adenocarcinoma of the vagina (B). Rationale: DES, a synthetic estrogen, causes vaginal epithelial changes; ovarian cancer (A) and other conditions (C, D) are not directly linked.
Question 4 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 5 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).