CFC syndrome is a genetically heterogenous condition. Missense mutations have been identified in BRAF, KRAS, MEK1 and MEK2. We have reported here a KRAS mutation in a baby girl with an early clinical diagnosis of CFC syndrome associated with a large ulcerating hemangioma. Although ectodermal abnormalities have been described in all individuals with this condition, features such as ichthyosis and hemangioma have been previously found only in those patients carrying a mutation in BRAF, and not in KRAS. The findings we have described contrast with these observations. The relatively high frequency of hemangiomas in CFC syndrome suggests that defects in the expression of the MAPK pathway may alter endothelial cell proliferation. Increased understanding of how the molecular pathways with which defects in CFC syndrome predispose affected individuals to hemangiomas might offer insights into the pathogenesis of this common childhood tumour in the general population.