The role of dental evaluation and cephalometric analysis in the diagnosis of Williams-Beuren syndrome.

Williams-Beuren syndrome (WS) is a genetic condition with an incidence of 1 in 20,000-50,000 live births. The syndrome consists of supravalvular aortic stenosis, characteristic dysmorphic facial features named "elf face" and intellectual disability. Early diagnosis of the syndrome is important since many of its features require treatment, and the prognosis can be dramatically improved by early recognition and management. This developmental disorder is well known to be clinically heterogeneous, making diagnosis difficult if based on the clinical picture. However, genetic testing is expensive and it is not cost effective to screen all patients based on clinical suspicion. Our goal was to develop a novel clinical screening method that would be sensitive, specific, inexpensive and readily available. We performed cephalometric analysis and dental evaluation of 33 patients with genetically proven WS. Cephalometric analysis of soft tissues showed that with normal SNA, SNB and ANB angles, the lips were in front of the line of harmony. This finding was present in all WS patients (n = 33) but in none of the age-matched controls (n = 100). No other differences were found between WS and control patients. This cephalometric finding is specific and sensitive for WS and can be used in the diagnostic procedure, whereas none of the conventional dental evaluations are useful.