What is Craniosynostosis?

A baby’s skull is comprised of separate bones connected by sutures, rather than fused bone. These sutures allow the skull to expand as the brain grows. If any (or all) of these sutures close prematurely, the skull cannot grow/form as it usually would, resulting in what is known as craniosynostosis.  
  
In the case of a craniosynostosis-related syndrome, current research points to problems in the genes responsible for producing proteins to regulate cell growth rate and/or cell growth limits. Apert, Crouzon, Muenke, Pfeiffer, and Saethre-Chotzen syndromes fall into this craniosynostosis-related category.

During early development in the womb, a baby's FGFR-2 protein is supposed to direct immature cells to become bone cells. This protein also tells immature cells when to stop becoming bone cells. However, in craniosynostosis, we believe the FGFR-2 gene may not produce the FGFR-2 protein properly, so that it doesn’t know when to stop telling tissue to become bone. Without clear, “stop bone production” information, the soft sutures of the skull form fused bone before they should—impacting growth patterns and resulting in malformation(s).

Register to Access the Craniosynostosis Forum.

 

Craniosynostosis-Related Syndromes

Apert Syndrome
Present at birth, Apert syndrome is caused by an early closing (fusion) of the skull’s side (coronal) sutures, resulting in a variety of symptoms. Apert syndrome is relatively rare, as it occurs with a frequency of one in 160,000 live births.  


Crouzon Syndrome
Present at birth, Crouzon syndrome results from an early closing (fusion) of several of the skull’s sutures—always including the side (coronal) sutures. Closely related to Apert syndrome, Crouzon patients do not share all the physical anomalies associated with Apert syndrome.  Crouzon syndrome occurs with a frequency of one in 60,000 live births.
 

Muenke Syndrome
The most common craniofacial syndrome, Muenke, results from an early closing (fusion) of the skull’s side (coronal) sutures. Muenke syndrome occurs with a frequency of one in 30,000 live births—about twice as common as Apert, Crouzon and Saethre-Chotzen syndromes, and three times as common as Pfeiffer syndrome.  
  

Pfeiffer syndrome
Pfeiffer syndrome results from an early closing (fusion) of up to three of the skull’s sutures (coronal, lambdoidal, and sometimes, sagittal). The physical manifestations of Pfeiffer syndrome closely match those of Crouzon syndrome. Pfeiffer syndrome occurs with a frequency of one in 100,000 live births.  
   

Saethre-Chotzen Syndrome
Closely related to Crouzon syndrome, Saethre-Chotzen syndrome results from an early closing (fusion) of the skull’s side (coronal) sutures or back (lambdoidal) suture. Saethre-Chotzen syndrome occurs with a frequency of one in 25-50,000 live births.