Alternative Name :Branchial arch syndrome.
Crouzon syndrome is a genetic disorder of Chromosome 10. Specifically, this syndrome affects the first branchial (or pharyngeal) arch, which is the precursor of the maxilla and mandible. Since the branchial arches are important developmental features in a growing embryo, disturbances in their development create lasting and widespread effects.
This syndrome is named after Octave Crouzon, a French physician who first described this disorder. He noted the affected patients were a mother and her daughter, implying a genetic basis. First called “craniofacial dysostosis”, the disorder was characterized by a number of clinical features. This syndrome is caused by a mutation in the fibroblast growth factor receptor II, located on chromosome 10.
Breaking down the name, “craniofacial” refers to the skull and face, and “dysostosis” refers to malformation of bone.
Now known as Crouzon syndrome, the disease can be described by the rudimentary meanings of its former name. What occurs in the disease is that an infant’s skull and facial bones, while in development, fuse early or are unable to expand. Thus, normal bone growth cannot occur. Fusion of different sutures leads to different patterns of growth of the skull. Examples include: trigonocephaly (fusion of the metopic suture), brachycephaly (fusion of the coronal suture), dolichocephaly (fusion of the sagittal suture), plagiocephaly (unilateral premature closure of lambdoid and coronal sutures), oxycephaly (fusion of coronal and lambdoidal sutures), Kleeblattschaedel (premature closure of all sutures).
In the United States it is estimated to affect 1 per 60,000 live births.It is responsible for approximately 4.8% of all cases of craniosynostosis. Crouzon syndrome affects individuals of all ethnic backgrounds. It may be inherited or it may occur spontaneously.
Incidence of Crouzon syndrome is currently estimated to occur in 1 out of every 25,000 people out of the general population. There is a greater frequency in families with a history of the disorder, but that doesn’t mean that everyone in the family is affected (as referred to above).
Crouzon syndrome is usually diagnosed in infancy because of its particular face and skull deformities, which are:
•Early fusion of the bones of the skull (craniosynostosis), causing a misshapen head
•The skull problems may push the brain down (tonsillar herniation), and may obstruct the flow of cerebrospinal fluid (hydrocephalus)
•The nose and upper jaw appear sunken in because of poor bone growth in the face (midface hypoplasia)
•The eyes may appear to pop out (exophthalmos or proptosis) for the same reason (midface hypoplasia)
There may be other internal problems with the face and head such as narrow or absent ear canals, problems with the teeth and palate, and problems with the nose and sinuses. In some individuals with Crouzon syndrome (about 18%), two or more bones of the neck may be fused together.
Some individuals with the syndrome (about 5%) may also have a skin disorder called acanthosis nigricans, in which lesions of darkened, thickened skin are present.
Associations with mutations in the genes of FGFR2 and FGFR3 have been identified as cause of Crouzon syndrome. This FGFR2 gene provides instructions for making a protein called fibroblast growth factor receptor 2. Among its multiple functions, this protein signals immature cells to become bone cells during embryonic development. Mutations in the FGFR2 gene probably overstimulate signaling by the FGFR2 protein, which causes the bones of the skull to fuse prematurely.
The condition is inherited in an autosomal dominant way, so that each child of a person with Crouzon syndrome has a 50 per cent chance of inheriting the condition. However, in about half of all cases the syndrome has resulted from a new mutation (that is, neither parents were affected).
Like Apert syndrome, Crouzon syndrome may be more common among children born to older fathers.
Diagnosis of Crouzon syndrome usually can occur at birth by assessing the signs and symptoms of the baby. Further analysis, including radiographs, magnetic resonance imaging (MRI) scans, genetic testing, X-rays and CT scans can be used to confirm the diagnosis of Crouzon syndrome.
Like other genetic conditions, Crouzon’s cannot be ‘cured’. But with the right help and care, most children lead a relatively normal life.
Surgery is typically used to prevent the closure of sutures of the skull from damaging the brain’s development. Without surgery, blindness and mental retardation are typical outcomes. Craniofacial surgery is a discipline of plastic surgery. To move the orbits forward, plastic surgeons work with neurosurgeons to expose the skull and orbits and reshape the bone. To treat the midface deficiency, plastic surgeons can move the lower orbit and midface bones forward (this does not need neurosurgical assistance). For jaw surgery, either plastic surgeons have experience to perform these operations. It is rare to wear a custom-fitted helmet (or cranial band) for several months after surgery as that is only for single-suture “strip craniectomy” repair. Crouzon patients tend to have multiple sutures involved, most specifically bilateral coronal craniosynostoses, therefore an open operation is used rather than the strip craniectomy with helmeting.
Excessive fluid around the brain (hydrocephalus) may need to be drained by inserting a tube called a shunt. Other specialist help, for example, to treat dental, eye or ear, nose and throat problems, is often needed.
Long-term supportive treatments such as speech therapy, psychological and educational help, and genetic counselling for the family are also important in helping the child to reach their potential.
Once treated for the cranial vault symptoms, Crouzon patients generally go on to live a normal lifespan.
You may click to learn more if you have specific questions about Crouzon syndrome.
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.
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