FGFR1 and Pfeiffer syndrome: Craniosynostosis, characterized by premature fusion of cranial sutures due to increased osteoblast proliferation or differentiation, or to increased mineralizing functions of osteoblasts, are also caused by mutations in FGFR1 and FGFR2. Crouzon, Apert, Beare-Stevenson with cutis gyrata, Bent-bone dysplasia, Saethre-Choetzen, Jackson-Weiss and Pfeiffer syndromes are all caused by activating mutation in FGFR2 gene and the consequent accelerated osteoblast maturation in the sutures [165,166,167].