FGFR2 and Cowden syndrome 1: Previously, syndromic CS was defined by the occurrence of one of the frequent and well-known syndromes: Apert, Muenke, Saethre–Chotzen, Pfeiffer, or Crouzon, caused by genetic variants in the FGFR2, FGFR3, TWIST1, FGFR1/2, and FGFR2 genes, respectively [1, 8].