For instance, in humans, Apert syndrome, characterized by premature fusion of the bilateral coronal sutures and severe syndactyly of the feet and hands, is caused by Ser252Trp and Pro253Arg mutations of the FGFR2 gene in the D2-D3 linker region, which leads to FGFR2 gain-of-function in a ligand-dependent manner (Slaney et al., 1996; Ferreira et al., 1999; Ibrahimi et al., 2001; Andreou et al., 2006; Ko, 2016; Kunwar et al., 2017). The gene discussed is FGFR2; the disease is Apert syndrome.