Prenatal Diagnosis—Applications of Amniocentesis Which of the following genetic or chromosomal conditions can be diagnosed prenatally using amniocentesis, where fetal cells and amniotic fluid are analyzed by karyotyping and/or molecular tests?

Introduction / Context:
Amniocentesis is a prenatal diagnostic procedure performed typically after 15 weeks of gestation to obtain amniotic fluid containing fetal cells and soluble markers. The collected material is analyzed by cytogenetics, fluorescence in situ hybridization, and DNA-based assays to detect chromosomal aneuploidies and specific single-gene disorders. This question assesses awareness of the clinical scope of amniocentesis.

Given Data / Assumptions:

• The options include a chromosomal disorder (Down's syndrome) and two single-gene disorders (cystic fibrosis and sickle cell anemia).
• Amniotic fluid yields fetal cells for karyotype and DNA extraction.
• Parental carrier status or screening may guide targeted testing.

Concept / Approach:
Amniocentesis supports two major diagnostic streams: (1) karyotyping or chromosomal microarray for aneuploidies and structural rearrangements, and (2) molecular testing for known pathogenic variants in single genes when the familial mutation is known or targeted panels are indicated. Therefore, all listed conditions are diagnosable by appropriate post-procedure laboratory techniques.

Step-by-Step Solution:

Verification / Alternative check:
Clinical workflows routinely combine cytogenetics and PCR/NGS-based assays on amniotic samples for comprehensive evaluation when indicated by risk factors or ultrasound findings.

Why Other Options Are Wrong:

• Each individual condition alone underestimates the scope of amniocentesis.
• “None of these” contradicts established practice.

Common Pitfalls:
Confusing screening (e.g., NIPT) with diagnostic testing; underestimating molecular testing capability on amniotic cells.

Final Answer:
All of these