In order to test the hypothesis that mutations in additional genes encoding proteins involved in IL11RA signaling could also be associated with craniosynostosis, the five coding exons of IL11 were sequenced in 46 patients with various forms of craniosynostosis as well as the five coding exons of IL6 in 28 patients and the 14 coding exons of the GP130 in 44 patients. The gene discussed is IL6; the disease is craniosynostosis.