A term neonate has low-set malformed ears, micrognathia, flexed overlapping fingers, rocker-bottom feet, short sternum, and an omphalocele. The mother had marked polyhydramnios and weak fetal movements during pregnancy. Which chromosomal abnormality is most likely?
- A Trisomy 13
- B Trisomy 21
- C Trisomy 18 ✓
- D Deletion of chromosome 5p
Correct answer: C. Trisomy 18
Explanation
Clenched fists with overlapping fingers, rocker-bottom feet, micrognathia, low-set ears, omphalocele, and reduced fetal activity are the classic constellation of Edwards syndrome, trisomy 18. Trisomy 13 (Patau) is suggested by holoprosencephaly, cleft lip and palate, polydactyly, and microphthalmia, which are absent here. Deletion 5p produces cri-du-chat syndrome with a cat-like cry and hypertelorism, not clenched overlapping fingers.
Reference: Nelson Textbook of Pediatrics, 22nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.