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Thanatophoric dysplasia — RACP Paediatrics MCQ

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HardGeneticsThanatophoric dysplasiaRACP Paediatrics

A newborn presents with severe micromelic dwarfism, macrocephaly with a cloverleaf skull, and very short curved femurs with a 'telephone receiver' appearance on X-ray. The infant has severe respiratory insufficiency. What is the most likely diagnosis?

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Correct answer: E — Thanatophoric dysplasia

Thanatophoric dysplasia is the most common lethal skeletal dysplasia. It presents with severe micromelic shortening, macrocephaly (sometimes cloverleaf skull/kleeblattschädel), narrow thorax, and telephone receiver-shaped femurs on X-ray. It is caused by FGFR3 mutations (de novo, dominant). It is almost invariably lethal in the neonatal period due to respiratory insufficiency.

Reference: RACP Paediatric Curriculum – Genetics; RCH Melbourne – 2023