Cytogenetic analysis of products of conception from a spontaneous first-trimester miscarriage is performed. Which chromosomal abnormality is the single most common finding?
- A 45,X monosomy
- B Trisomy 21
- C Trisomy 16 ✓
- D Triploidy
Correct answer: C. Trisomy 16
Explanation
About half of all first-trimester spontaneous losses are chromosomally abnormal, and autosomal trisomies account for the largest group. Trisomy 16 is the single most common autosomal trisomy identified in abortuses and is almost always lethal in utero. Monosomy 45,X is the most common single abnormality overall but ranks below the combined autosomal trisomies, and triploidy accounts for roughly 15 to 20 percent. This knowledge explains why most sporadic miscarriages carry a low recurrence risk.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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