INTRODUCTION:

Crouzon syndrome is a rare genetic disorder that may be evident at birth or during infancy. The disorder is characterized by distinctive malformation of the skull and facial (craniofacial) region. Such abnormalities may vary greatly in range and severity from case to case, including variations among affected family members. However, in most infants with crouzon syndrome, the fibrous joints between the cranial sutures close prematurely (craniosynostosis). In addition, facial abnormalities typically include proptosis owing to shallow orbits: divergent strabismus or exotropia,ocular hypertelorism, and a small, underdeveloped upper jaw(hypo plastic maxilla), with protrusion of the lower jaw (relative mandibular prognathism).multiple staged surgeries are the general treatment plan for children with crouzon syndrome. With proper treatment, children can be productive and active members of mainstream society.

Definition/ meaning:

Crouzon syndrome, also called craniofacial dysostosis, is one of a large group of facial birth defects in which there is abnormal craniofacial fusion (joining between some of the bones of the skull and of the face). This fusion does not allow the bones to grow normally, affecting the shape of the head, appearance of the face and the relationship of the teeth. (Figure 1)

Figure: 1 Child with Crouzon Syndrome

Historical overview:

In 1912, Dr. Octave Crouzon described the hereditary syndrome of craniofacial dystosis in a mother and son. He described the triad as skull deformities, facial anomalies, and exophthalmoses. Premature craniosynostosis, midfacial hypoplasia and exophthalmos form the triad now known as Crouzon Syndrome.

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).

Incidence and Genetic causes:

Crouzan syndrome occurs in approximately 1 in 25,000 births worldwide and makes approximately 4.8 of all cases of craniosynostosis. Crouzon Syndrome is caused normally by a mutation of the FGFR2 gene (fibroblast growth factor receptor-2) on Chromo-some 10. Less commonly it is caused in the FGFR3 gene on Chromosome 4. The syndrome frequently occurs by a spontaneous mutation in the gene. If both parents are unaffected, the chances of a second child being born with Crouzon syndrome are extremely small. However, if one parent is affected, the chances that any pregnancy will result in a child with this syndrome is 1 out of 2 (50% risk). For this reason, it is very important that both parents of an affected child be thoroughly examined before any recurrence risks are quoted to them.

Main Symptoms:

There are some main symptoms that children with Crouzon Syndrome display. These are:

Ø A misshapen head caused by early fusion of the bones of the skull (craniosynostosis)

Ø Wide-set bulgy eyes caused by shallow eye sockets. The eyes may also not be aligned.

Ø Low set ears

Ø A nose that is beak shaped

Ø An underdeveloped upper jaw (under bite) and a protruded chin

Other associated symptoms relate to dental, hearing, the spine, sinuses and breathing, and there can be webbing of toes, and a shortened femur and humerus, may also have a skin disorder called acanthosis nigricans, in which lesions of darkened, thickened skin are present.

Diagnostic testing:

o Physical findings:

Crouzon Syndrome commonly begins during the first year and usually completes by the second or third year coronal and sagittal sutures are most commonly i8nvloved, resulting in a high prominent forehead. Ridging of the skull is usually palpable. The most common ocular abnormalities reported are shallow orbits, ocular proptosis, orbital hypertelorism, strabismus, optic atrophy, exposure keratitis and unexplained loss of visual acuity and hearing acuity. ‘

o Laboratory analysis:

More than 50% of children with crouzon syndrome have FGFR2 mutations on molecular analysis. FGFR2 mutations are also observed in Apert syndrome, Pfeiffer syndrome and Jackson-Weiss syndrome. All children with associated acanthosis nigricans have the FGFR3 ala 391-to-glu mutation.

o Imaging studies:

· Skull and cervical radiographs

· 3D Computer tomography (CT) scan

· Magnetic resonance imaging (MRI)

Treatment

The multi-disciplinary team who will care for a child with Crouzon Syndrome usually consists of a plastic surgeon, neurosurgeon, oral surgeon/orthodontist/dentist, speech therapist, respiratory doctors, audiologist, ophthalmologist and Ear Nose & Throat doctors. It is essential to have a good pediatrician who can monitor general health and co-ordinate. The goal is to stage reconstruction to coincide with facial growth patterns, visceral function and psychosocial development. In the newborn period, some potential problems that may need to be addressed include respiratory difficulties, feeding problems, neurologic complications such as hydrocephalus and the potential risk of developmental delay.

Multiple staged surgeries are the general treatment plan for the children with Crouzan syndrome. In Crouzan syndrome And Apert syndrome, synostosis of 2 or more cranial sutures may be involved, thus producing a risk for increases intracranial pressure and greater change of hydrocephalus. Because of the complexity of the surgery, it is common to be prosecuted in stages. In the 1^st year of life, it is preferred to release the synostotic sutures of the skull to allow adequate cranial volume to allow for brain growth and expansion. Skull reshaping may need to be repeated as the child grows to give the best possible results, if necessary midfacial advancement and jaw surgery can be done to provide adequate orbital volume and reduce the exophthalmus to correct the occlusion to an appropriate functional position and to provide for a more normal appearance. Plastic surgery may also be beneficial. It is one of the few syndromes in which the cosmetic results of the surgery can be strikingly effective. Note the differences in facial appearance between figures (figure: 2)

Parent teaching:

1. Be certain that the diagnosis is correct. Crouzon resembles several other syndromes and not all physicians are aware of this.

2. Consult the geneticist can provide the necessary evaluation and information.

3. Meet other individuals and families affected by similar facial differences by joining a parent support group.

CONCLUSION:

Crouzon syndrome is a generic disorder caused by mutant gene. Crouzon syndrome is an autosomal dominant disorder diagnosed in infancy and referred to a major hospital that has a craniofacial unit. Medical care focuses on managing the symptoms and surgically correcting problems. A team of specialists are involved in the care. An understanding of these abnormalities is necessary so the pediatric nurses can make the appropriative referral to insure the children receive the best available care.

REFERENCES:

1. L. E. O. Crouzon. Dysostose cranio-faciale héréditaire. Bulletin de la Société des Médecins des Hôpitaux de Paris, 1912, 33: 545-555.

2. Reardon W, Winter RM, Rutland P, Pulleyn LJ, Jones BM, Malcolm S (September 1994). "Mutations in the fibroblast growth factor receptor 2 gene cause Crouzon syndrome". Nat. Genet. 8 (1): 98–103. doi:10.1038/ng0994-98. PMID 7987400.

3. Meyers GA, Orlow SJ, Munro IR, Przylepa KA, Jabs EW (December 1995). "Fibroblast growth factor receptor 3 (FGFR3) transmembrane mutations in Crouzon syndrome with acanthosis nigricans". Nat. Genet. 11 (4): 462–4. doi:10.1038/ng1295-462. PMID 7493034.

4. James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). Saunders. ISBN 0-7216-2921-0.

5. Vajo Z, Francomano CA, Wilkin DJ. (February 2000). "The molecular and genetic basis of fibroblast growth factor receptor 3 disorders: the achondroplasia family of skeletal dysplasias, Muenke craniosynostosis, and Crouzon syndrome with acanthosis nigricans". Endocrine Reviews 21 (1): 23–39. Doi: 10.1210/er.21.1.23. PMID 10696568

6. Crouzon O.Dynsostose cranio-faciale Hereditary,Bullmem SOC Med Hosp Paris 1912:33:545-55

7. Fries Pd ,Katowitz Ja.Congenital Craniofacial Anomalies Of Ophthalmic Importance. Surv Ophthalmol 1990:35(2):87-119.

8. Dodge HW,Wood MW,kennedy RLJ. Craniofacial Dyostosis: Crouzon’s disease, Pediatrics 1959:98-106.

9. Gines E Rodriguez-Pichardo a Jorquera e. crouzon diseases with acanthosis nigricans and Melanocytic Nevi.Pediatr Dermatol 1996:13(1):18-21.

Received on 17.09.2013 Modified on 28.11.2013

Int. J. Adv. Nur. Management 2(2): April- June, 2014; Page 103-105