FGFR1 and Pfeiffer syndrome: Pfeiffer Syndrome, either in familial or sporadic cases, has been associated with fibroblast growth factor receptor 1 and 2 (FGFR1 locus 8p11.2-p11.1, OMIM 136350; and FGFR2 locus 10q26, OMIM 176943) gene mutations.4,5 Severe midface hypoplasia and exorbitism are more likely to be associated with FGFR2 gene mutation.