Symptoms of Crouzon Syndrome
The facial features of babies with Crouzon syndrome vary widely.
Craniosynostosis (the early closing of one or more of the sutures that separate the bony plates of the skull) in Crouzon syndrome most often occurs prior to birth. But it can occur later, during the first two or three years of life.
Some babies with Crouzon syndrome are born with an abnormal head shape (tall and narrow from front to back), wide-set prominent eyes (due to shallow eye sockets), small beak-like nose and small midface.
Some babies with Crouzon syndrome develop craniosynostosis after birth so that the head shape changes over time.
The eye findings are usually apparent at birth. The eye sockets are positioned further apart and are shallow, so the eyes appear to protrude. The eyes may not align properly so the gaze is outward.
Late onset (5 to 10 years old) craniosynostosis has been reported in several children with Crouzon syndrome who suffer from headaches and vision changes with a relatively normal head shape.
Other neurological problems include an increased risk to develop hydrocephalus (excess fluid on the brain) (30%) or Chiari malformation (abnormality of the back of the brain).
About 97% of people with Crouzon syndrome have normal intelligence.
Slower growth of midface bones results in a progressive difference between the upper and lower jaw. Over time the upper jaw appears smaller and the lower jaw appears to jut outward.
The palate (roof of the mouth) may be very tall and narrow such that the teeth of the upper jaw are crowded and positioned behind the lower jaw during chewing. Rarely there is a cleft palate (gap in the roof of the mouth).
The nose is small and beak-like.
If there is difficulty in breathing the infant may require placement of a surgical tracheostomy (breathing tube in the windpipe).
Conductive (bone) hearing impairment is noted in about 55% of people with Crouzon syndrome, with some infants born with a complete absence of ear canals.
Children with Crouzon syndrome may need to wear hearing aids for hearing loss.
People with Crouzon syndrome do not have the abnormalities of the hands and feet noted in other craniosynostosis syndromes, though sometimes they will have restricted elbow movement.
Cervical spine (neck) abnormalities have been noted in 30% of people with Crouzon syndrome.
Some people with Crouzon syndrome develop a skin abnormality called acanthosis nigricans.
This involves the development of patches of darker pigmented (colored), thickened (velvety feeling) skin on the neck and eyelids and around the mouth. These children have the form of Crouzon syndrome caused by mutations in FGFR3.
The abnormal facial features of a child with Crouzon syndrome typically become more apparent with growth.
Crouzon Syndrome Diagnosis
To diagnose this condition, your doctor will examine your child’s skull carefully. The shape will help the doctor tell whether any sutures have fused.
Computed tomography (CT) imaging can give the doctor more information. A CT scan is an X-ray procedure that takes a computer-enhanced cross-sectional view of the body.
Your child’s facial features will help the doctor determine whether they have Crouzon syndrome or another condition.
Your child may need X-rays of their spine and hand to confirm the diagnosis.
The doctor may test a sample of cells from your child’s skin to check for acanthosis nigricans, too.
Your doctor may also do genetic tests that show whether your child has a mutation that causes Crouzon syndrome.
For parents of a child diagnosed with Crouzon syndrome, a careful family history and genetic evaluation is recommended to provide recurrence risk information.
Genetic testing for mutations in the Crouzon syndrome genes is available.
More than 50% of people with the clinical diagnosis of Crouzon syndrome without acanthosis nigricans have an FGFR2 gene mutation detectable by commercial laboratories.
Acanthosis nigricans is a skin abnormality that involves the development of patches of darker pigmented (colored), thickened (velvety feeling) skin on the neck and eyelids and around the mouth.
All people with Crouzon syndrome linked with acanthosis nigricans have a specific mutation (A391E) in the FGFR3 gene. Genetic counseling before testing is recommended.