Premature fusion of coronal, sphenofrontal and ethmoidal sutures seen in
The question mentions the coronal, sphenofrontal, and ethmoidal sutures. I remember that craniosynostosis syndromes like Crouzon and Apert involve multiple sutures. Crouzon's is associated with premature fusion of coronal and sphenofrontal sutures, leading to a characteristic facial appearance. Apert syndrome often involves coronal suture fusion as well but might have other features like syndactyly. Pfeiffer syndrome is another possibility but typically involves different sutures.
Wait, the ethmoidal suture is part of the ethmoid bone's development. Crouzon syndrome does involve the ethmoid, so that's a key point. Let me verify: Crouzon's is caused by FGFR2 mutations and affects coronal, sphenofrontal, and ethmoidal sutures. That fits the question. So the correct answer should be Crouzon syndrome.
Now, the incorrect options would be other syndromes. Apert has coronal fusion but also syndactyly. Pfeiffer has bicoronal synostosis and broad thumbs. Plagiocephaly is more about unilateral coronal fusion without the other sutures. So each wrong option can be ruled out based on their specific features.
The clinical pearl here is that Crouzon is the key syndrome affecting those three sutures. Also, remembering the associated mutations (FGFR2) might help. I need to make sure the explanation clearly differentiates each option and explains the correct one's mechanism.
**Core Concept**
Premature fusion of cranial sutures, particularly the coronal, sphenofrontal, and ethmoidal sutures, is a hallmark of **Crouzon syndrome**, a type of craniosynostosis caused by mutations in the **FGFR2 (fibroblast growth factor receptor 2)** gene. This leads to a flattened midface, hypertelorism, and increased intracranial pressure due to restricted skull growth.
**Why the Correct Answer is Right**
Crouzon syndrome is characterized by **premature closure of the coronal, sphenofrontal, and ethmoidal sutures**, resulting in a **brachycephalic** (short, wide) skull shape and **midface hypoplasia**. The fusion of these sutures disrupts normal cranial expansion, compressing the developing brain and altering facial bone growth. FGFR2 mutations cause abnormal signaling in osteoblasts, accelerating suture ossification. This syndrome is **autosomal dominant**, with no associated limb abnormalities (unlike Apert syndrome).
**Why Each Wrong Option is Incorrect**
**Option A:** *Apert syndrome* involves coronal suture fusion but is distinguished by **syndactyly** (webbed fingers/toes) and **midface hypoplasia**.
**Option B:** *Pfeiffer syndrome* causes bicoronal synostosis and **broad thumbs/index fingers**, but not ethmoidal suture involvement.
**Option C:** *Plagiocephaly* refers to **unilateral