Craniosynostosis is characterized by premature fusion of one or more cranial sutures and is associated with mutations in fibroblast growth factor receptor (FGFR) genes. Here we describe a novel mutation (1084+1G>A) in the FGFR2 gene of a patient with isolated bicoronal synostosis. We detected two isoforms that result from the mutation and are characterized, respectively, by exon skipping and the use of a cryptic splice site. Interestingly, the alternatively spliced forms of FGFR2 appear to induce fusion of the cranial sutures suggesting that the mutation acts via a gain-of-function mechanism rather than a loss of protein functionality.