An infant has bilateral radial ray anomalies (absent thumbs, hypoplastic radius) with a large ostium secundum atrial septal defect. Mutation of which gene is most likely?
- A TBX4
- B PITX1
- C TBX5 ✓
- D HOXA13
Correct answer: C. TBX5
Explanation
Holt-Oram syndrome results from TBX5 mutation and combines upper limb (radial ray) defects with cardiac septal abnormalities. TBX4 with PITX1 specifies hindlimb identity rather than forelimb, and HOXA13 mutation causes hand-foot-genital syndrome without cardiac lesions, so these distractors fail on both limb territory and the associated heart defect.
Reference: Moore and Persaud, The Developing Human, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.