Beare-Stevenson Syndrome

At a glance

Sporadic disorder with craniosynostosis, skin, and anogenital anomalies.

Synonym

Beare-Stevenson Cutis Gyrata Syndrome.

Incidence

About 25 individuals have been described. No ethnic or gender predilections have been identified.

Genetic inheritance

This autosomal dominant syndrome has been linked to mutations in the fibroblast growth factor receptor 2 (FGFR2) gene, which has been mapped to chromosome 10q26. There are several different FGFR2 mutations, the most common ones being Tyr375Cys and Ser372Cys (amino acid substitution of cysteine for tyrosine at residue 375 and cysteine for serine at residue 372 of the FGFR-gene, respectively), however, phenotypically they seem to be identical. Only sporadic cases have been described. This gene is also involved in other craniosynostosis syndromes (eg, ☞Acrocephalosyndactyly Syndromes [Crouzon Syndrome, Apert Syndrome, Pfeiffer Syndrome]). A possible paternal age effect has been discussed, but has not been confirmed.

Diagnosis

Based on the clinical picture and family history. Confirmation requires molecular mutation analysis.

Clinical aspects

Craniosynostosis with acrocephaly or cloverleaf skull is the most consistent finding. Other common craniofacial features may include frontal bossing, downslanting of the palpebral fissures, hypertelorism, proptosis (shallow orbits), midface hypoplasia with choanal stenosis or atresia, high or narrow palate (less commonly cleft palate), bifid uvula, micrognathia, flat nasal bridge, low-set and posteriorly rotated ears and low-set anterior and posterior hairlines. Narrow ear canals have been described in some patients and profound bilateral conductive hearing loss in one. Natal teeth (erupted teeth at birth) and hypodontia of the primary and permanent teeth have been reported in a few patients. Central nervous system anomalies mainly consist of occlusive hydrocephalus secondary to aqueduct stenosis mainly in patients with cloverleaf skull. One patient also had agenesis of the corpus callosum. Developmental delay can be severe. Upper airway obstruction with severe respiratory distress requiring immediate intubation after birth is frequent and tracheostomy later on is necessary in almost two-thirds of patients. Tracheal cartilaginous sleeve (TCS) anomaly can be associated with Beare-Stevenson Syndrome and is not always easy to diagnose on bronchoscopy. This congenital airway malformation is characterized by vertically fused tracheal rings appearing as a continuous cartilaginous segment that can extend from the subglottis all the way down to the main bronchi with minimal or no posterior pars membranacea. TCS is believed to alter the mechanical properties (increased rigidity/decreased elasticity and distensibility) of the trachea and airflow dynamics, reducing the efficacy of natural airway protective and clearing mechanisms. Children with Beare-Stevenson Syndrome are at risk for sudden death and surviving children have a tracheostomy, which for some experts would support early evaluation for TCS and consideration for tracheostomy. However, several patients with tracheostomy still experience intermittent cyanosis requiring bag ventilation or die from sudden death. The vast majority of patients have skin anomalies presenting ...