Apert syndrome. Craniosynostosis with syndactyly .
Incidence
Unaffected parents who have a child with Apert syndrome will 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 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 Apert 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. In Apert syndrome, fusion of the digits requires orthopedic surgery. Particular management issues for Apert syndrome include alertness for excessively noisy breathing in association with poor weight gain, since these children are at risk for airway obstruction. Cervical spine x-rays should be part of the initial evaluation, and surveillance for hydrocephalus and increased intracranial pressure is important before and after operations. Impaired absorption of cerebrospinal fluid may explain the 23% of children with Apert syndrome who experienced hydrocephalus after operation, and this complication was associated with intellectual deficit (average IQ 72.5). Mutations in the fibroblast growth factor receptor 2 (FGFR2) gene have been described in Apert, Crouzon, Jackson-Weiss, and Pfeiffer syndromes. These syndromes clearly have a genetic basis and exhibit autosomal dominant inheritance.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
Clinical features.