A 6-year-old girl evaluated for recurrent shoulder dislocation has a chest radiograph showing absence of both lateral clavicles, a bell-shaped thorax, and multiple wormian bones. Dental examination reveals failure of eruption of permanent teeth. What is the MOST likely diagnosis?
- A Pyknodysostosis
- B Osteogenesis imperfecta
- C Cleidocranial dysplasia ✓
- D Hypophosphatasia
Correct answer: C. Cleidocranial dysplasia
Explanation
Cleidocranial dysplasia, caused by RUNX2 mutation, classically combines partial or complete aplasia of the clavicles allowing shoulder approximation, delayed closure of fontanelles with wormian bones, and multiple supernumerary teeth with failure of eruption. Osteogenesis imperfecta shows osteopenia and fractures rather than clavicular aplasia. Pyknodysostosis features generalised osteosclerosis with short distal phalanges. Hypophosphatasia shows rickets-like metaphyseal changes with low alkaline phosphatase, not absent clavicles with dental anomalies.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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