Family: Education: Descriptions of Disorders
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CROUZON SYNDROME
CROUZON SYNDROME
What Is Crouzon Syndrome?
Crouzon syndrome is a form of craniosynostosis,
a group of conditions marked by abnormalities in the shape of the skull. These
conditions occur when the bones of the skull, which normally are separated by
a narrow space at birth, fuse together too early.
Skull Growth and Development
The skull may appear to be a single, solid structure, but it is actually made
up of several separate bones. The separation of skull bones allows a slight
degree of flexibility of an infant’s head, which serves multiple purposes early
in life. During birth, this flexibility allows the baby’s skull to "mold," or
temporarily change shape, as the head passes through the birth canal. As the
child grows, the skull bones expand to accommodate the growing brain. Eventually,
at around age 11 or 12, the skull bones fuse along the sutures, and skull growth
is complete.
Craniosynostosis
Craniosynostosis results when some or all of the sutures between the skull
bones fuse together earlier than normal. When this happens, the growing brain
exerts pressure on the skull, which cannot expand enough to accommodate it.
Like a balloon being pinched on one side as it is being blown up, the skull
grows abnormally to make room for the brain.
Craniosynostosis can take a number of forms, depending on which skull sutures
are affected. The various types of craniosynostosis are broadly categorized
into non-syndromal—when the skull abnormalities occur without other defects—and
syndromal—when craniosynostosis is part of a cluster of features that
make up a syndrome. Abnormalities of the hands and feet, such as extra or fused
digits, are some of the characteristics that may accompany syndromal craniosynostosis.
What Is Crouzon Syndrome?
Crouzon syndrome is distinguished from most other types of syndromal craniosynostosis
by the absence of obvious hand or foot abnormalities. The condition is present
in about one of every 60,000 live births. Although it is a rare disorder, it
makes up about 5% of all cases of craniosynostosis.
In most cases of Crouzon syndrome, the coronal sutures of the skull
are affected. These sutures lie across the top of the head, between the frontal
and parietal bones (see illustration). Fusion of the coronal sutures results
in brachycephaly, or a foreshortened head shape, as skull growth is restricted
in a forward direction. The fused coronal sutures cause the skull to grow sideways
and upward, causing a flattened forehead and increased height and width of the
head.
Clinically, the most common features of Crouzon syndrome are protruding eyes
and a flattened or dish-shaped face. In a person with Crouzon syndrome, the
foreshortened forehead makes the eye sockets shallower than normal, which causes
the eyes to bulge out of their sockets. This condition is known as proptosis.
Sometimes the eyes protrude to the point where the eyelids do not completely
close around them during sleep. The result is dryness and irritation of the
eyes, and in some cases, infection or visual impairment. About half of patients
with Crouzon syndrome have visual problems related to proptosis. Also typical
are eyes that are not aligned in the same direction or that are set widely apart.
Other eye problems include atrophy (wasting) of the optic nerve, which causes
blindness in about 7–10% of patients.
Other problems that accompany Crouzon syndrome are hearing loss, which occurs
in about half of patients; dental problems, such as crowding of teeth; abnormalities
of the cervical spine (neck); and a skin condition called acanthosis nigricans.
This latter condition consists of dark, velvety patches of skin on the neck
and eyelids and around the mouth. A small number of patients also have cleft
lip with or without cleft palate or a high, arched palate. These palate
abnormalities can cause problems with hearing, nasal breathing, and/or speech.
If not corrected, the craniosynostosis that is part of Crouzon syndrome can
cause pressure on the growing brain to the point where blindness, hearing loss,
and death ensue. This is especially true if all the skull sutures have fused
early in a child’s life.
What Causes Crouzon Syndrome?
Crouzon syndrome is due to a genetic mutation—a change that takes place
in a cell’s DNA during cell division. Gene mutations can be caused by external
factors, but many occur spontaneously. Before birth, spontaneous mutations normally
occur on a regular basis during cell division as the fetus grows. The vast majority
of spontaneous mutations are harmless, but some are the cause of problems such
as Crouzon syndrome.
The mutation that causes Crouzon syndrome may be passed down from a parent
who has the condition, or it may arise spontaneously in a family with no history
of the condition. In the latter cases, the mutation seems to be linked to advancing
age of the father. A parent with Crouzon syndrome has a 50% chance of passing
down the disorder to each of his or her children. The severity of the disorder
varies widely, so the child of a parent with Crouzon may have a lesser or greater
degree of severity of the condition.
How Is Crouzon Diagnosed?
Crouzon syndrome is usually diagnosed on the basis of clinical features of
the face and skull. The diagnosis is suggested by the combination of craniosynostosis,
especially of the coronal sutures; a flattened appearance of the middle of the
face; and protruded eyes, together with the absence of the hand or foot abnormalities
seen in other craniosynostosis syndromes. Although the diagnosis can be confirmed
by a genetic test, this may not necessarily be done. Because the mutation that
causes Crouzon syndrome has also been found to be responsible for other craniosynostosis
syndromes, this genetic test may not distinguish between related syndromes.
The diagnosis, then still rests on clinical examination by a physician familiar
with these conditions.
How Is Crouzon Treated?
With the exciting advances in gene therapy that are being made every day, it
may one day be possible to correct the genetic defect that causes Crouzon syndrome.
At present, however, the treatment of this condition is chiefly surgical.
With surgery, skull deformities can be corrected, the eye sockets made deeper,
and dental problems addressed. The number and type of operations needed depend
on the specific problems and their severity. In severe cases, the skull sutures
may have closed before birth, requiring surgery very early in the infant’s life.
Because of the multiple problems often seen in Crouzon patients, treatment
is best carried out by a team of specialists. These typically include cosmetic
surgeons, ear-nose-throat surgeons, dentists and orthodontists, geneticists,
and audiology and speech therapists.
Finding Information
OMIM
123500
Genetest
- FGFR 2 - 176943
Finding Support
The Children’s Craniofacial Association is a national nonprofit organization
dedicated to improving the quality of life for people with facial differences
and their families. The organization addresses the medical, financial, psychosocial,
emotional, and educational concerns relating to craniofacial conditions, advocating
and promoting awareness for individuals with facial differences.
Children’s Craniofacial Association
P.O. Box 280297
Dallas, TX 75228
Phone: (972) 240-7730
Toll-free: (800) 535-3643
Fax: (972) 240-7607
Web site: www.masterlink.com/children
AboutFace International is a national voluntary health organization
dedicated to providing individual and family support to those who have facial
differences. The organization offers information, practical advice, and the
opportunity to network with others who share similar concerns and experiences.
AboutFace International
P.O. Box 93
Limekiln, PA 19535
Phone: (610) 689-4476
Toll-free: (800) 225-3223
Fax: (610) 689-4479
E-mail: Info@aboutfaceinternational.org
Web site: www.aboutfaceinternational.org
Forward Face is a self-help group affiliated with the Institute of Reconstructive
Plastic Surgery at the New York University Medical Center and the National Foundation
for Facial Reconstruction. The organization is dedicated to helping affected
individuals and family members successfully cope with craniofacial disorders.
Forward Face
317 East 34th Street
Room 901
New York, NY 10016
Phone: (212) 684-5860
Toll-free: (800) 393-3223
Fax: (212) 684-5864
Web site: Forward
Face
FACES: National Craniofacial Association is a nonprofit organization
who provides families with financial assistance for travel to major medical
centers for reconstructive surgery.
FACES
P.O. Box 11082
Chattanooga, TN 37401
Phone: (423) 266-1632
Toll-free: (800) 332-2373
Fax: (423) 267-3124
E-mail: faces@mindspring.com
Web site: www.faces-cranio.org
The World Craniofacial Foundation provides educational information and
financial assistance with the secondary costs associated with medical treatment,
such as food, transportation, and lodging, to parents of children with craniofacial
disorders. It also provides teaching materials to doctors in other countries
and publishes quarterly newsletters on craniofacial disorders.
World Craniofacial Foundation
7777 Forest Lane, Suite C-621
P.O. Box 515838
Dallas, TX 75251-5838
Phone: 972-566-6669
Toll-free: 1-800-533-3315
Fax: 972-566-3850
E-mail: worldcf@worldnet.att.net
Web site: www.worldcf.org
On the Web
The Crouzon Support Network helps individuals and families affected
by Crouzon syndrome and other craniofacial anomalies.
www.crouzon.org
Reading Matter
Children with Facial Differences is an excellent resource for
help in coping with the medical, emotional, social, educational, legal, and
financial challenges presented by the facial differences of one’s children.
Children with Facial Differences: A Parent’s Guide
Hope Charkins, MSW
Woodbine House, 1996
Author: Deborah J. Shuman
Date: November 1, 2000
Disclaimer: Links to support groups and relevant web sites do not signify
an endorsement.
© 2000 The Johns Hopkins University
Read
the article with links to term definitions
Last Updated:
12/16/03
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