Crouzon syndrome is a genetic disorder characterized by premature fusion of the skull bones (craniosynostosis) and abnormal growth of the bones of the face, specifically the eye sockets and the midface. This may affect the shape of the head, appearance of the face, and the growth of the jaw. It was first described in 1912 by the French neurosurgeon, Dr. O. Crouzon.
The majority (about 97%) of people with Crouzon syndrome have normal intelligence. The facial features vary greatly with each infant or child. Some infants may have an abnormal head shape, wide-set prominent eyes due to shallow eye sockets, a small beak-like nose, and a small midface (midface hypoplasia or underdeveloped upper jaw).
The Craniofacial Team of Texas has extensive experience with Crouzon syndrome and the associated symptoms and treatments. We take a multidisciplinary approach to address individual needs of our patients and their families.
Crouzon Syndrome and Genetics
How common is Crouzon Syndrome? Crouzon syndrome is seen in about 16 per one million newborns. It is the most common craniosynostosis syndrome.
Crouzon syndrome is associated with mutations in the FGFR2 gene. This gene provides instructions for making a protein called fibroblast growth factor receptor 2, which in return prompts immature cells to become bone cells early in development. It is thought that mutations in the FGFR2 gene “overstimulate” this process, which causes the bones of the skull to fuse prematurely.
In some cases, an affected person inherits the mutation from one affected parent (autosomal dominant pattern). This means that only one copy of the altered gene is needed to cause the disorder. It can, however, also occur in people with no family history of the disorder, which means it is a new, spontaneous mutation.
Why is Crouzon Syndrome called a syndrome?
A syndrome is a condition characterized by a set of associated symptoms. Though individuals with Crouzon syndrome may vary in how they each present, we know what constellation of symptoms need to be monitored. For example, an underdeveloped midface (midface hypoplasia) may cause problems with breathing by physically obstructing the airway (obstructive sleep apnea). Early symptoms may be feeding difficulties and poor weight gain in infancy prior to overt respiratory symptoms. Others may not develop symptoms until childhood. Shallow eye sockets may cause eyes to appear prominent or protrude out and may require special care for potentially over exposed corneas.
Unlike children with single suture craniosynostosis, children with Crouzon syndrome may have multiple sutures affected (multisuture craniosynostosis). Our section on Craniosynostosis discusses the premature fusion of the cranial sutures in detail but a brief discussion is helpful here. The skull is made up of multiple plates (or bones) that are not fully fused together until adulthood to allow for rapid growth of brain volume in early infancy and childhood. Premature fusion of one of the sutures restricts growth of the skull (or cranium) perpendicular to the length of the suture affected. As brain growth continues, pressure is applied on the remaining unfused sutures to allow for compensatory growth. Therefore, depending on which suture prematurely fuses, the infant will take on a very characteristic head shape. Left untreated over a period of time, craniosynostosis could result in increased pressure on the developing brain (increased intracranial pressure). As mentioned prior, infants with Crouzon syndrome may have multiple sutures affected, resulting in the inability to compensate for the growth needed to keep intracranial pressure normal and the developing brain “happy”. Intervention may be needed sooner for them compared to a child with only a single suture involved. In addition, the premature fusion of the sutures may occur as early as in utero or not until later in their childhood. Because of the variability in presentation and severity, children with Crouzon syndrome must be approached individually. We follow our patients from birth to adulthood and incorporate the parents and families in the decision making process.
What surgical treatments are available Crouzon Syndrome?
While all children with Crouzon syndrome need to be monitored closely, the amount of intervention varies greatly based on each individual and their associated symptoms. Not all of the interventions discussed below will be needed for each child.
Airway Surgery for Crouzon Syndrome
Midface hypoplasia may require surgical advancement of the bones in childhood to allow unobstructed breathing (Le Fort III osteotomy). This also allows for the proper alignment of the upper jaw (maxilla) and the lower jaw (mandible) in older patients. Some infants with severe midface hypoplasia may require placement of a tracheostomy tube to stabilize their breathing until a more definitive surgical correction can take place.
An infant may also benefit from moving the lower jaw forward (mandibular distraction osteogenesis) if this is the primary source of airway obstruction.
Eye Care in Crouzon Syndrome
Special care of the eyes including an evaluation by an ophthalmologist in addition to a craniofacial team will be needed. Frontoorbital advancement may be needed to protect the eyes from overexposure and to reposition misaligned eyes in order to avoid visual impairment.
Cranial Vault Reconstruction Surgery for Crouzon Syndrome
Craniosynostosis is treated by cranial vault reconstruction. Cranial vault reconstruction is the repositioning and reshaping of the skull (cranium), allowing expansion of the intracranial volume needed for brain growth. This allows the developing brain to function in a healthy environment without increased intracranial pressure. The timing of surgery will depend on the number of sutures affected and severity of the deformity. Children with Crouzon syndrome will need to be monitored for signs of increased intracranial pressure throughout infancy and childhood. Signs of increased intracranial pressure may include irritability in infancy, delayed developmental milestones, headaches in older children, visual changes, and lethargy (feeling sluggish). Infants or children with more than one suture affected (multisuture craniosynostosis) are at a higher risk for developing these symptoms sooner than those with only one suture affected (single suture craniosynostosis).
Orthodontic Treatment for Crouzon Syndrome
Our orthodontist, who specializes in children with craniofacial differences, will keep a close watch on the development of your child’s teeth, bite, and jaw alignment. Orthodontic treatment in Crouzon syndrome may be needed for overcrowding of the teeth in the upper jaw (maxilla), expansion of the palate, and alignment of the upper and lower jaw (mandible). Her orthodontic treatment is closely coordinated with any potential jaw surgery (orthognathic surgery).
Hearing, Speech and Psychosocial Development in Crouzon Syndrome
Children with Crouzon syndrome will also need close monitoring of their hearing and speech development. Their psychosocial development also needs special care and support as they often face unique challenges at an early stage of life. The Craniofacial Team of Texas includes craniofacial surgeons, an orthodontist, a pediatrician, speech therapists, nurse coordinators, physician assistants, nurse practitioners, and social workers with extensive experience with Crouzon syndrome. We work closely and in coordination with our specialized colleagues in otolaryngology (ear, nose, and throat), ophthalmology, and neurosurgery, as well as your child’s primary care provider.
If you would like more information about craniosynostosis, please contact the Craniofaical Team of Texas.