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Dermatology > PEDIATRIC DISEASES
Crouzon Syndrome
Article Last Updated: Jan 23, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Grazyna Szybejko-Machaj, MD, PhD, Assistant Professor, Department of Dermatology and Venereology, University of Medicine at Wroclaw, Poland
Editors: Jacek C Szepietowski, MD, PhD, Professor and Vice-Head, Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Poland; Michael J Wells, MD, Associate Professor, Department of Dermatology, Texas Tech University Health Sciences Center; Robert A Schwartz, MD, MPH, Professor and Head of Dermatology, Professor of Medicine, Professor of Pediatrics, Professor of Pathology, Professor of Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Author and Editor Disclosure
Synonyms and related keywords:
craniofacial dysostosis, Crouzon-Apert syndrome, premature obliteration and ossification of two or more sutures, premature ossification of coronal and sagittal sutures, craniostenosis, Crouzon's syndrome
Background
Crouzon syndrome was described in 1912 as one of the varieties of craniofacial dysostosis caused by premature obliteration and ossification of two or more sutures, most often coronal and sagittal. Virchow introduced the term craniostenosis. The type of obliterated sutures determines the type of craniostenosis. Oxycephaly, scaphocephaly, wedge skull, and oblique head are differentiated. Crouzon syndrome with oxycephaly and Apert syndrome with oxycephaly and syndactylia (acrocephalosyndactyly) are the most common cases of dysostosis. Some authors connect those syndromes as one, calling it Crouzon-Apert syndrome, but symptomatologic differentiation makes classification difficult. Acanthosis nigricans is the main dermatologic manifestation of Crouzon syndrome.
Pathophysiology
Dysplasias of the skeleton (including craniofacial dysostosis) are caused by the malformations of the mesenchyme and ectoderm. The unknown teratogenic factors are taken into account. Dysplasias are inherited in an autosomal dominant pattern. Mutation of the gene for fibroblast growth factor receptor 2 (FGFR2) could be responsible for Crouzon syndrome. Moreover, the mutation in the transmembrane region of FGFR3 was detected in this syndrome.
Frequency
International
Incidence is very low. Crouzon syndrome is seldom observed all around the world.
Mortality/Morbidity
High intracranial pressure caused by disproportion between craniostenosis and brain growing may lead to death.
Race
Race is not noted as a predisposing factor.
Sex
Sex factor does not play any role.
Age
Deformation of bony face is visible just after the birth. Other syndrome factors reveal themselves with time.
History
- Bony face deformity is observed at birth, followed with time by other factors of the syndrome.
- Patients report headache.
- Convulsions often occur; mental retardation is frequently observed.
Physical
- Coronal and sagittal sutures are obliterated; fontanels remain not obliterated and pulsating for a long time.
- Lateral and anteroposterior flattening of the acro-cranium is observed, growing only at the vertical axis.
- Anteroposterior diameter is smaller than transverse diameter.
- The forehead is high and wide.
- Wide face and hypoplastic maxilla producing pseudoprognathism are observed.
- Deviation of the nasal septum, narrowed or obliterated anterior nares, and wide beaked nose are present.
- Hypertelorism, divergent squint, eyelid scheme antimongoloid, and upper eyelid falling "frog face" are observed.
- The upper lip is shortened and sometimes cleaved.
- Progressing optic nerve atrophy leads to vision impairment because of the intracranial hypertension.
- Impairment of hearing indicates disorders of the middle ear.
- Malocclusion, malposed teeth, hypsistaphylia, rhinolalia, and dysphasia are noted.
- Characteropathy is often observed.
- Short stature and no physiologic spinal curvature are observed. Children are straight as a reed.
- Koilosternia rarely occurs.
- Skin usually is dark.
- Syndromic acanthosis nigricans appears in the axillary fossa, mouth angular, and on the lips in childhood.
Causes
This syndrome is inherited in an autosomal dominant pattern.
Other Problems to be Considered
Apert syndrome/acrocephalosyndactylia
Franceschetti-Zwahlen syndrome
Marie-Sainton syndrome
Greig syndrome
Lab Studies
- Histopathologic examination of skin changes - Acanthosis nigricans
Imaging Studies
- Skull, spine, and hand radiography is usually necessary to confirm the diagnosis.
- Skull radiography reveals the following:
- Oxycephaly - Acro-cranium (most characteristic), obliterated sutures (mostly coronal, sagittal)
- Deep digitate impression, shallow eye sockets (exophthalmos)
- Turkish saddle deepened with osseous sternum connecting anterior and posterior clinoid processes
- Shortened anterior cranial fossa
- Underdeveloped lateral nasal sinuses
- Tympanic membranes fixed oblique, narrowed external auditory canals, absence of mastoid processes pneumatization, and small pyramids with symptoms of sclerosis
- On spine radiography, lumbarization and the presence of bifid spinous process are possible, and slight symptoms of achondroplasia may be visible.
- Radiographic examination of the metacarpal bones and fingers reveals slight achondroplasia.
Other Tests
- Ophthalmologic examination with ophthalmoscopy
- Laryngologic examinations with audiography
- General physical examination with ECG
- Psychiatric examinations and psychological testing
- Stomatologic examination
- EEG - Low-voltage, increased convulsive excitability
Histologic Findings
Histologic features of acanthosis nigricans include hyperkeratosis, acanthosis, and papillomatosis. In the basal layer, the amount of pigment cells is also increased in the upper dermis. No difference exists in histologic features of acanthosis nigricans among symptomatic, benign, and malignant forms.
Surgical Care
A neurosurgical procedure is recommended in cases of intracranial hypertension leading to further optic atrophy. This surgery is difficult, and the procedure must be considered and undertaken in stages. Plastic surgery of the face could be of great help. It is one of the few syndromes where the cosmetic results of the surgery can be strikingly effective.
Consultations
Consultations with ophthalmologists, laryngologists, neurologists, psychiatrists, and stomatologists are usually required.
Further Inpatient Care
- Ophthalmologists and neurologists should monitor patients with Crouzon syndrome.
The authors and editors of eMedicine gratefully acknowledge the contributions of previous author, Mieczyslawa Miklaszewska MD, to the development and writing of this article.
| Media file 1:
Acrocephaly, beaked nose, "frog face," and pseudoprognathism of Crouzon syndrome. |
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| Media file 2:
Malposed teeth and acanthosis nigricans around the mouth in Crouzon syndrome. |
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| Media file 3:
No physiological spinal curvature is observed in Crouzon syndrome. |
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| Media file 4:
Acanthosis nigricans of the axillary fossa in Crouzon syndrome. |
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| Media file 5:
Short stature and dark skin of Crouzon syndrome. |
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Crouzon Syndrome excerpt Article Last Updated: Jan 23, 2007
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