Abstract Introduction The role of elastin in tympanic retractions and chronic otitis media is not well established. Williams Syndrome (WS), a pathology related to a mutation in the elastin gene, could generate tympanic retractions. Objective To compare the prevalence of tympanic retractions among patients with WS and controls. Methods WS patients (n= 43 ears) and controls (n= 130 ears) were evaluated by digital otoscopic examination and the degree of tympanic membrane retraction was classified by 2 blinded experienced otolaryngologists. Results The agreement rate between the evaluators was 71.1% for pars tensa and 65% for pars flaccida retraction (p< 0.001). The pars tensa and pars flaccida retractions are present in patients with WS after an adjusted residue of respectively - 2.8 and - 2.6 (p= 0.011 and p= 0.022) compared with controls. Conclusions Tympanic membrane retractions are not more common in the WS group when compared with controls.

A síndrome de Angelman (SA) e a síndrome de Prader-Willi (SPW) são doenças neurogenéticas distintas; entretanto, já foi observada sobreposição clínica entre essas duas patologias. Descrevemos mais um caso de um paciente apresentando o fenótipo da SPW e exames moleculares compatíveis com a SA. Apesar do fenótipo da SPW, o teste da metilação do DNA no gene SNRPN revelou padrão compatível com a SA. A análise citogenética e análise por FISH mostraram ambos os cromossomos 15 normais e a análise de polimorfismo de microssatélite mostrou heterozigozidade para marcadores dentro e fora da região 15q11-13. A presença destes casos atípicos pode ser mais freqüente que o esperado e salientamos que a análise da metilação do DNA é importante para o diagnóstico correto de deficiência mental, hipotonia congênita e obesidade.

Angelman syndrome (AS) and Prader-Willi syndrome (PWS) are distinct human neurogenetic disorders; however, a clinical overlap between AS and PWS has been identified. We report on a further case of a patient showing the PWS phenotype with the AS molecular defect. Despite the PWS phenotype, the DNA methylation analysis of SNRPN revealed an AS pattern. Cytogenetic and FISH analysis showed normal chromosomes 15 and microsatellite analysis showed heterozygous loci inside and outside the 15q11-13 region. The presence of these atypical cases could be more frequent than previously expected and we reinforce that the DNA methylation analysis is important for the correct diagnosis of severe mental deficiency, congenital hypotonia and obesity.