observed a FGFR3 mutation in as many as 31% of the cases with nonsyndromic coronal synostosis, thus showing that FGFR abnormalities play an important role in nonsyndromic craniosynostosis.In terms of syndromic craniosynostosis not only do FGFR3 and TWIST genes feature, but also FGFR1 and in particular FGFR2, which has been reported in 90% of the syndromic craniosynostoses such as Apert, Crouzon, Peiffer and Jackson–Weiss. The mutations can be divided into mutations that lead to gain of function (in FGFR genes) and mutations that lead to loss of function (in TWIST genes). Craniosynostosis is therefore likely the result of a disturbance in the fine balance that regulates the multiplication and maturation of the precursor bone cells in the cranial sutures.The familial rate, which is different for nonsyndromic and syndromic cases, provides an important clue. In the nonsyndromic cases, a positive family history is found in 2% of the cases with sagittal suture closure and in 6% to 11%  of the cases with coronal suture closure. Cranial sutures
The mesenchyme above the meninges undergoes intramembranous ossification forming the neurocranium. The neurocranium consists of several bones, which are united and at the same time separated by fibrous sutures. This allows movement of the separate bones in relation to one another; the infant skull is still malleable.
The points to look at are: eye position, eye symmetry and twisting of the nasal tip.The implications of the deformities that are seen are extensively discussed under phenotype. Syndromal craniosynostosis presents with a skull deformity as well as deformities affecting other parts of the body. Clinical examination should in any case include evaluation of the neck, spine, digits and toes. Medical imaging
Radiographic analysis by performing a computed axial tomographic scan is the gold standard for diagnosing craniosynostosis.Plain radiography of the skull may be sufficient for diagnosing a single suture craniosynostosis and should therefore be performed, but the diagnostic value is outweighed by that of the CT-scan. Not only can the sutures be identified more accurately, thus objectively demonstrating a fused suture, but also evaluation of the brain for structural abnormalities and excluding other causes of asymmetric growth are possible at the same time. In addition to this, CT-scanning can visualize the extent of skull deformity, thereby enabling the surgeon to start planning surgical reconstruction. Classification
There are several ways to classify craniosynostosis. For example, one can consider the number of closed sutures. If only one of the four sutures is prematurely closed (single suture craniosynostosis), the craniosynostosis is referred to as simple (or isolated). Whereas when two or more sutures are no longer open, the craniosynostosis is complex. A second classification scheme gives a clinical description of the resulting shape of the skull. This will be further discussed under phenotype. A third classification involves the presence or absence of an identified craniofacial syndrome.