Pfeiffer syndrome type 2: further delineation and review of the literature.

We present 5 unrelated patients, 3 boys and 2 girls, with Pfeiffer syndrome (PS) type 2. They all had cloverleaf skull, severe proptosis, ankylosis of the elbows, broad thumbs and/or broad halluces and variable accompanying anomalies. We review the literature on all subtypes of PS. Most patients with PS type 2 died shortly after birth. Causes of death include pulmonary problems, brain abnormalities, prematurity and post-operative complications. DNA studies were performed in 3 of the 5 patients. Two of them showed a 1036T --> C mutation in the fibroblast growth factor receptor 2 (FGFR2) gene, that was earlier reported in PS and in Crouzon syndrome. Probably most, if not all, PS type 2 cases are caused by a de novo mutation in the FGFR2 gene or in another, yet unidentified gene. To date all type 2 cases have been non-familial. A low recurrence risk for parents can be advised.