A neonate has midline cleft lip and palate, microphthalmia, polydactyly, and a scalp defect over the vertex. Echocardiography shows a large septal defect. Which additional finding would be most consistent with the underlying chromosomal abnormality?

• A Holoprosencephaly on cranial ultrasound ✓
• B Overlapping flexed fingers with hypotonia
• C Absent thymus with hypocalcemia
• D Cystic hygroma of the neck

Explanation

The combination of midline defects (cleft lip and palate, scalp defect or cutis aplasia), microphthalmia, postaxial polydactyly, and cardiac defects points to trisomy 13 (Patau syndrome). Holoprosencephaly is the classic associated brain malformation, reflecting disruption of midline development. Overlapping clenched fingers suggest trisomy 18, absent thymus with hypocalcemia suggests 22q11 deletion, and cystic hygroma suggests Turner syndrome.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.