FGFR2 and Pfeiffer syndrome: Pathogenic variants in one of the most frequently affected genes, fibroblast growth factor receptor 2 (FGFR2), are associated with a multitude of phenotypically distinct syndromes, such as Crouzon, Apert and Pfeiffer syndromes, among others (Anderson et al., 1998; Kan et al., 2002; Kimonis et al., 2007; Neilson and Friesel, 1995; Wenger et al., 1993).