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High incidence of GJB2 mutations during screening of newborns for hearing loss in Austria.

Research paper by Reinhard R Ramsebner, Romana R Volker, Trevor T Lucas, Gertrude G Hamader, Klara K Weipoltshammer, Wolf-Dieter WD Baumgartner, Franz J FJ Wachtler, Karin K Kirschhofer, Klemens K Frei

Indexed on: 09 May '07Published on: 09 May '07Published in: Ear and hearing



Abstract

The aim of the present study was to evaluate gap junction protein beta2 (GJB2) genetic testing within a national neonate screening program for hearing loss (HL) in a European population.Neonatal cases of nonsyndromic HL (N = 21) were identified by postpartal otoacoustic emissions (OAE) and brain stem electric response audiometry (BERA) analysis. GJB2 testing was performed by direct sequencing.Mutations in GJB2 were found in 15 of 21 children (71.4%) identified by neonatal audiological screening. The 35delG mutation in GJB2 was found homozygous in 10 cases (47.6%) and also as a clear cause of HL as the heterozygous alterations 35delG/del311-324 and 35delG/L90P. In a single case, L90P/R143Q was also identified as a cause of HL. In 3 HL cases that were not identifiable during initial OAE testing, homozygous 35delG and 35delG/R184P defined the genetic basis for HL in 2 cases, whereas one case had wild-type GJB2.Our findings of the high mutation rate in the Austrian population, especially in neonates identified during the newborn screening program, confirm the importance of screening for mutations in GJB2.

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