Interaction Between Audiology And Genetics In The Study Of A Family: The Complexity Of Molecular Diagnosis And Genetic Counseling [interação Entre Audiologia E Genética No Estudo De Uma Família: A Complexidade Do Diagnóstico Molecular E Do Aconselhamento Genético]

Hearing loss is a multifaceted condition with many etiologies, among which genetic mutation is. Therefore, it is important to connect audiological investigation to etiological diagnosis. Aim: this study aims to establish the audiological and genetic profiles of three non-syndromic children with sensorineural hearing loss. Materials and method: three brothers aged 3, 5 and 16 were enrolled in this study. They were submitted to behavioral and electrophysiological hearing tests and molecular studies. Results: the hearing tests showed moderate to moderately severe bilateral symmetric sensorineural hearing loss and an accentuated descending slope. Transient and Distortion Product Otoacoustic emissions were absent in the two younger children. ABR showed a bilateral moderately severe to severe sensorineural hearing loss. P300 showed bilateral normal latencies in the older brother. Molecular tests showed that the two younger children were heterozygote for mutation 35delG on gene GJB2. Conclusion: The combination of speech and hearing tests and genetic analysis allows for the etiologic diagnosis of seemingly similar hearing loss cases, which however display different genetic backgrounds. Molecular studies must be comprehensive enough to avoid precipitated diagnosis which may impair genetic counseling. © Revista Brasileira de Otorrinolaringologia. All Rights reserved.745698702Godinho R, Keogh I, Eavey R. Perda Auditiva Genética. Rev. Bras. Otorrinolaringol. [online]. Jan./Fev. 2003, 69, no. 1 [cited 06 Novembro 2005], p. 100-104. Available from World Wide Web: http://www.rborl.org.br/ conteudo/acervo/print-acervo.asp?id=35. ISSN 1806-9312Azevedo MF. Avaliação audiológica no primeiro ano de vida. In: Lopes Filho, OC (org.). Tratado de Fonoaudiologia. São Paulo, Editora Roca Ltda.1997, cap. 11 p.239-63Russo, I.C.P., Santos, T.M.M., A Prática da Audiologia Clínica (2005) São Paulo: Cortez editoraGranato L, Pinto CF, Ribeiro MQ. Perda Auditiva de Origem Genética. In: Lopes Filho OC (org.). Tratado de Fonoaudiologia. São Paulo: Editora Roca1997, cap. 2 p. 25-53Pfeilsticker, L.N., Stole, G., Sartorato, E.L., Delfino, D., Maciel-Guerra, A.T., Genetic investigation of non-syndromic hereditary deafness (2004) Rev Bras Otorrinolaringol, 70, pp. 182-186Petit, C., Genes responsible for human hereditary deafness: Symphony of a thousand (1996) Nature Genet, 14, pp. 385-391Van Camp, V., Willems, P.J., Smith, R.J.H., Non-syndromic hearing impairment: Unparalleled heterogeneity (1997) Am J Hum Genet, 60, pp. 758-764Estivill, X., Fortina, P., Surrey, S., Rabionet, R., Melchionda, S., DÁgruma, L., Connexin-26 mutations in sporadic and inherited sensorineural deafness (1998) Lancet, 351, pp. 394-398Antoniadi, T., Rabionet, R., Kroupis, C., Aperis, G.A., Economides, J., Petmezakis, J., High prevalence in the Greek population of the 35delG mutation in the connexin 26 gene causing prelingual deafness (1999) Clin Genet, 55 (5), pp. 381-382Green, G.E., Scott, D.A., McDonald, J.M., Woodworth, G.G., Sheffield, V.C., Smith, R.J., Carrier rates in the midwestern United States for GJB2 mutations causing inherited deafness (1999) JAMA, 281 (23), pp. 2211-2216Storm, K., Willcox, S., Flothmann, K., Van Camp, G., Determination of the carrier frequency of the common GJB2 (connexin-26) 35delG mutation in the Belgian population using an easy and reliable screening method (1999) Hum Mutat, 14 (3), pp. 263-266Oliveira CA. Determinação da freqüência dos alelos 35delG no gene da conexina 26 em amostras da população brasileira. Campinas, 2005. [Tese de doutorado curso de Ciências Biomédicas, Faculdade de Ciências Médicas - UNICAMP]Piatto, V.B., Bertollo, E.M.G., Sartorato, E.L., Maniglia, V., Prevalence of GJB2 mutations and the del(GJB6-D13S1830) mutation in Brazilian patients with deafness (2004) Hearing Research, 196, pp. 87-93Del Castillo, F.J., Rodriguez-Ballesteros, M., Alvarez, A., Hutchin, T., Leonardi, E., Oliveira, C.A., A novel deletion involving the connexin-30 gene, Del(GJB6-d13s1854), found in trans with mutations in the GJB2 gene (connexin-26) in subjects with DFNB1 non-syndromic hearing impairment (2005) J Med Genet, 42 (7), pp. 588-594Prezant, T.R., Agapian, J.V., Bohlman, M.C., Bu, X., Oztas, S., Qiu, W.Q., Mitochondrial ribosomal RNA mutation associated with both antibiotic-induced and non syndromic deafness (1993) Nat Genet, 4, pp. 289-294Neto, J.F.L., Pereira, A.C., O que há de Novo no Campo da Genética Molecular da Surdez: Descoberta de Genes para Surdez. Rev Bras Otorrinolaringol[online] (2005) Mar/Abr 1999(65)2 [cited, pp. 106-113. , http://www.rborl.org.br/conteudo/acervo/print-acervo.asp?id=1452.ISSN1806-9312, 06 Outubro, Available from World Wide WebSartorato, E.L., A genética da surdez (2000) Pesquisa Fapesp, pp. 26-28. , janeiro/fevereiroRamalho, A.S., (1986) As hemoglobinopatias hereditárias: Um problema de Saúde Pública no Brasil, pp. 119-128. , Ribeirão Preto, Editora da Sociedade Brasileira de Genética;Faria, I., Perda auditiva de origem genética: Uma retrospectiva da literatura. São Paulo (2001), Monografia de Especialização em Audiologia clínica, CediauLloyd, L.L., Kaplan, H., (1978) Audiometric interpretation: A manual of basic audiometry, , Baltimore: University Park Press;Carhart, R., An improved method for classifying audiograms (1945) Laryngoscope, 55, p. 640Silman, S., Silverman, C.A., (1997) Auditory Diagnosis - Principles and Applications, , San Diego-London: Singular Publishing Group;Lopes Filho OC, Carlos RC. Emissões Otoacústicas. In: Lopes Filho, OC (org.). Tratado de Fonoaudiologia. São Paulo: Editora Roca1997. cap.10 p. 221-37Manual do usuário - Ero Scan - Etymotic Research1999Manual do equipamento Biologic - Evoked Potential User Manual BIO -LOGIC1998Musiek, F.E., Lee, W.W., Potenciais auditivos de média e longa latência - In: Perspectivas Atuais em Avaliação Auditiva - Org (2001) Musiek FE, Rintelmann WF. Barueri, pp. 239-267. , São Paulo: Editora Manole;McPherson, D.L., (1996) Late potentials of the auditory system (evoked potentials), , San Diego: Singular Press