RET and Crouzon syndrome: Single nucleotide substitutions in RET genes are responsible for a range of autosomal dominant syndromes, including Pfeiffer syndrome, Crouzon syndrome, Apert syndrome, achondroplasia, thanatophoric dysplasia, and multiple endocrine neoplasia types 2A and 2B (MEN2A and MEN2B) (Orioli et al., 1995; Kovac et al., 2013).