Atypical Skin Manifestations in FGFR2-Related Craniosynostosis Syndromes Broaden the Phenotypic Spectrum.

Crouzon syndrome (CS) and Beare-Stevenson syndrome (BSS) are craniosynostosis syndromes caused by mutations in the fibroblast growth factor 2 (FGFR2) gene. CS is more common (1 in 60,000 live births) than BSS, where fewer than 20 individuals have been reported. The cardinal features of BSS are craniosynostosis, cutis gyrata, acanthosis nigricans, skin furrows, skin tags, anogenital anomalies, and a prominent umbilical stump. Previously described individuals with BSS have typically had mutations in exon 11 of FGFR2. Here, we present 2 patients with CS who have significant skin manifestations and some phenotypic overlap with BSS. De novo mutations in exon 8 of FGFR2 were identified in both; one is a mutation (c.799T>C; p.Ser267Pro) previously identified in individuals with CS and the other a novel in-frame deletion (c.820_824delinsTT; p.Val274_Glu275delinsLeu). No mutations in exon 11 of FGFR2, where previously reported BSS mutations have been located, were identified. This case expands the phenotypic spectrum of CS and highlights the overlap between conditions caused by mutations in FGFR2.