Some patients with Couzon Syndrome will develop Acanthosis Nigricans, often during childhood (CAN Syndrome).


Chromosome affected: 4p16.3


Gene affected: fibroblast growth factor receptor 3 (FGFR3)


Mutation: substitution at position 391


Clinical features of CAN:

(1) craniosynostosis

(2) ocular proptosis

(3) midface hypoplasia

(4) choanal atresia

(5) mandibular prognathism (maxillary hypoplasia)

(6) hydrocephalus

(7) acanthosis nigricans


Patients usually have normal intellect and normal limbs.


The differential diagnosis includes Muenke syndrome which also affects FGFR3.


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