FGFR2 and Apert syndrome: Patients with congenital fibroblast growth factor receptor 2 (FGFR2) gain-of-function mutations (S252W or P253R FGFR2)—either germline (Apert syndrome) [55,56,57,58] or segmental somatic (acne nevus of Munro) [59,60,61,62,63]—develop acne during puberty and respond to isotretinoin treatment [64].