Crouzon syndrome. Craniosynostosis alone with normal hand findings.
Incidence
AD. Unaffected parents have a recurrence risk of less than 1%. Affected individuals, who will mostly have normal life expectancies and reproductive potential, will have a 50% recurrence risk with each pregnancy.
Clinical Characteristics
Although most patients with Apert or Crouzon syndrome will have fusion of the coronal suture, occasional ones will present with clover-leaf skull or other combinations of synostosis. Depending on the cause and distribution of fused sutures, it is the changes in skull shape that produce complications in the craniosynostosis disorders. With synostosis of the coronal (ear to ear) suture, undergrowth of the midface is common with malformation of the sphenoid bones behind the nose and flattening of the cranial base. Infants may have a huge fontanelle, extending from the lower forehead to the occiput. The nasal bridge is depressed and the nasal septum may be deviated. Narrowing of the posterior choanae (nasal passages) may occur and produce respiratory distress or heart failure. The small midface may also restrict the orbits, causing the eyes to bulge and become injured because of exposure and inadequate tearing. Palatal anomalies (cleft soft palate, highly arched palate) together with flattened cheekbones and protrusion of the jaw cause dental misalignment. Dental eruption may also be delayed. In Crouzon syndrome, there is risk for upper and lower airway obstruction. The smaller mouth and throat may cause symptoms of obstructive sleep apnea (cessation of breathing during sleep) and heart failure due to inadequate oxygenation (cor pulmonale). Surgical treatment involving resection of the palate, adenotonsillectomy, or even tracheostomy may be considered for symptomatic patients. Lower airway obstruction can result from narrowing or inflexibility of the trachea, causing difficulty in clearing secretions and possible damage from tracheal suctioning. Fusions of the neck spine can also occur in these syndromes, mandating cervical spine x-rays before attempting intubation for general anesthesia. Narrow respiratory structures can impair ear drainage, causing chronic otitis and hearing loss. The frequency of craniosynostosis is about 0.4-0.6 per 1000 live births. Unaffected parents have a recurrence risk of less than 1%. Affected individuals, who will mostly have normal life expectancies and reproductive potential, will have a 50% recurrence risk with each pregnancy.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
By clinical features. Several craniosynostosis syndromes have been associated with mutations in the fibroblast growth factor-2 gene, but DNA diagnosis is not routinely available.