The parents of a 3 month old infant with cystic fibrosis(CF) want to know how their child got this disease because no one in their families has CF. The nurse's basis for understanding that with CF:

Correct Answer: B

Rationale: CF is autosomal recessive; both parents must be carriers (B) for the child to inherit it. Mutation (A), extrachromosomal (C), or single carrier (D) don’t explain familial absence. Document: 'Both parents must be carriers of the CF gene.'

Correct Answer: D

Rationale: Complete androgen insensitivity syndrome (CAIS) is caused by mutations in the AR gene on the X chromosome, following an X-linked recessive pattern (Choice D). Phenotypic females (46,XY) inherit a mutated X from carrier mothers, with males unaffected as they have one X. Autosomal dominant (Choice A) and recessive (Choice B) don’t apply to X-linked traits. Mitochondrial (Choice C) involves maternal transmission, unrelated here. X-linked recessive fits CAIS’s genetics.

Correct Answer: B

Rationale: Macrophage activation syndrome is a severe complication of systemic JIA, marked by fever, organomegaly, and cytopenias from hemophagocytosis (EULAR criteria). Viral syndrome lacks specificity, hemolytic anemia doesn’t fit all findings, spleen failure is unclear, and DIC requires coagulopathy evidence.

Correct Answer: C

Rationale: Respiratory alkalosis shifts phosphorus intracellularly due to alkalemia, lowering serum levels (UpToDate). Acidosis (A, D) shifts it out, and B, E have minimal effect.

Correct Answer: B

Rationale: Turner syndrome with Y-chromosome material raises gonadoblastoma risk due to dysgenetic gonads (NORD). Other conditions (A, C-E) lack this link.