FGFR2 and acanthosis nigricans: The FGFR-related craniosynostosis spectrum includes PS, Apert syndrome, Jackson-Weiss syndrome, Beare-Stevenson syndrome, Crouzon syndrome, Crouzon syndrome with acanthosis nigricans, Muenke syndrome, and FGFR2-related isolated coronal synostosis (11,13,22).