IRF6 and Pfeiffer syndrome: SNPs in genes involved with syndromes were previously associated with a variety of facial measurements, for example, genes such as FGFR1 (e.g., Pfeiffer syndrome and Kallmann syndrome) (3), IRF6 (e.g., Van der Woude syndrome) (5), and RUNX2 (e.g., cleidocranial dysplasia syndrome) (4).