Karyotyping of products of conception from a sporadic 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 share. Among individual trisomies, trisomy 16 is the single most common and is almost always lethal in utero. Polyploidies such as triploidy and monosomy 45,X are the next common groups. Trisomy 21 fetuses more often survive to later gestation or birth, so it is not the leading finding among abortuses.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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