FGFR3 mutations and the skin: report of a patient with a FGFR3 gene mutation, acanthosis nigricans, hypochondroplasia and hyperinsulinemia and review of the literature.
Novel FGFR3 mutations creating cysteine residues in the extracellular domain of the receptor cause achondroplasia or severe forms of hypochondroplasia.
Despite its location within the same FGFR3 codon as the thanatophoric dysplasia type II mutation (Lys650Glu) and a similar effect on constitutive activation of the FGFR3 tyrosine kinase, the Lys650Met is not associated with cloverleaf skull or craniosynostosis.
Radiographically, all of the cases with the Lys650Glu substitution demonstrated straight femora with craniosynostosis, and frequently a cloverleaf skull (CS) was demonstrated.