Beare-Stevenson cutis gyrata syndrome (MIM 123790) is an autosomal dominant condition characterized by the furrowed skin disorder of cutis gyrata, acanthosis nigricans, craniosynostosis, craniofacial dysmorphism, digital anomalies, umbilical and anogenital abnormalities and early death. Many of these features are characteristic of some of the autosomal dominant craniosynostotic syndromes. Mutations in Crouzon, Jackson-Weiss, Pfeiffer and Apert syndromes have been reported in the FGFR2 extracellular domain. In Crouzon syndrome patients with acanthosis nigricans, a recurrent mutation occurs in the transmembrane domain of FGFR3. We now describe the detection of FGFR2 mutations in the Beare-Stevenson cutis gyrata syndrome. In three sporatic cases, a novel missense mutation was found causing an amino acid to be replaced by a cysteine; two had the identical Ty375Cys mutation in the transmembrane domain and one had a Ser372Cys mutation in the carboxyl-terminal end of the linker region between the immunoglobulin III-like (Iglll) and transmembrane domains. In two patients, neither of these mutations were found suggesting further genetic heterogeneity.