Molecular biology studies of sensorineural deaf Argentinean families and their relevance in the genetic counseling.

VIVIANA DALAMÓN; VANESA LOTERSZTEIN; LILIANA FRANCIPANE; BIBIANA DI PAOLI; GUSTAVO FRECHTEL; ENRIQUE MANSILLA; ANA BELEN ELGOYHEN

Rio de Janeiro-Brasil

Congreso; 3rd International Conference on Birth defects disabilities in the developing world; 2007

<!-- /* Font Definitions */ @font-face {font-family:PMingLiU; panose-1:2 1 6 1 0 1 1 1 1 1; mso-font-alt:新細明體; mso-font-charset:136; mso-generic-font-family:auto; mso-font-format:other; mso-font-pitch:variable; mso-font-signature:1 134742016 16 0 1048576 0;} @font-face {font-family:"@PMingLiU"; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-charset:136; mso-generic-font-family:auto; mso-font-format:other; mso-font-pitch:variable; mso-font-signature:1 134742016 16 0 1048576 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:PMingLiU; mso-ansi-language:ES-AR; mso-fareast-language:ZH-TW;} p.MsoPlainText, li.MsoPlainText, div.MsoPlainText {margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Courier New"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} @page Section1 {size:595.3pt 841.9pt; margin:42.55pt 49.55pt 70.85pt 42.55pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Genetically caused congenital deafness is a common trait affecting 1 in 2000 children. It is predominantly inherited in an autosomal recessive manner (75%). To date, over 40 different genes related with recessive deafness have been identified. The aim of this study was to perform a genetic screening in three different genes (GJB2, GJB6 and OTOF), in deaf patients from Argentina and to asses the importance of the identified mutations for the future genetic counseling and treatment of the patients. We analyzed patients with congenital non-syndromic deafness, presumably hereditary, as well as familial or late onset affected probands, derived from the Childhood Otorhinolaryngology and Genetic Services of the Hospital de Clínicas “José de San Martín” in Buenos Aires. Non-syndromic 41 probands (15 familial and 26 sporadic cases) with no deafness-acquired causes were genetically evaluated for mutations in the genes coding for connexin 26, 30 and otoferlin. 15 patients (37%) presented mutations in the GJB2 gene. None of the samples showed mutations in GJB6 or OTOF. Mutation c.35delG was identified in 8 of the 82 alleles (10%) of the GJB2 gene, resulting in the most frequent causing mutation in our analyzed population, in accordance with other reports worldwide. In addition, 5 sequence variations different from c.35delG, were identified in the coding region of the GJB2 gene in 12 patients: G12V, V27I, V37I, V95M, V153I. The present study demonstrates that different mutations in the GJB2 gene are prevalent in our Argentinean cohort and that other mutations in other genes are not as frequent here as reported elsewhere. These findings strengthen the importance of genetic screening in hearing-impaired patients for the contribution toward an adequate genetic counseling and treatment planning.