Abstract: In this multi-site, 5-year longitudinal study, infants with one of four types of single-suture craniosynostosis will be recruited: sagittal, metopic, right unilateral coronal, and left unilateral coronal (n = 250). A case-matched "control" group of healthy, normal infants (n = 250) will also be followed. The long-term objectives are to chart the neurobehavioral course of single-suture fusions and to better understand how the developing cranium affects human brain growth and function. Specific aims are to : (1) Clarify the neurobehavioral development and parental adjustment of infants with and without single-suture fusions at three time points in infancy and early childhood (just prior to cranioplastic surgery and twice post-surgery, at 18 and 36 months of age); (2) Among children with craniosynostosis, clarify relations between neurobehavioral development and abnormality in bone and brain tissue as indicated by measures taken from pre-surgery CT scans; (3) Among children with unicoronal synostosis, clarify relations between neurobehavioral development and presence of mutations; (4) Develop predictive models of 36-month outcomes for infants with craniosynostosis; and (5) Determine the relation between age of cranioplastic surgery and pre- and post-surgery neurobehavioral development.