Mutations in the GJB2 gene are found to account for approximately 50% of cases of autosomal recessive non-syndromic deafness. A 342-kb deletion truncating the GJB6 gene has been associated with autosomal recessive non-syndromic deafness, mostly as digenic inheritance of the Cx30 deletion/Cx26 mutation. The following retrospective study describes audiological features and genotypes of a large cohort of 628 hearing impaired patients who underwent genetic screening for the GJB2/GJB6 genes and received follow-up care at our centre between January 2002 and July 2008. Mutations in GJB2/GJB6 genes were found in over than 30% of cases. Twenty-seven different genotypes causing deafness in more than 25% of patients with either biallelic mutations or digenic inheritance GJB2/GJB6 were identified. The most frequent mutations of the GJB2 were 35delG, L90P, M34T, delE120 and R184P. The 342-kb deletion del(GJB6-D13S1830) was also quite frequent. In more than 14% of cases the cause of deafness was the homozygosis for the most common mutation among European people the 35delG. Although more than 70% of patients with biallelic/digenic inheritance of the Cx30 deletion/Cx26 mutation exhibit a severe to profound hearing loss, mild and moderate impairment were also found. Other clinical data such as course and degree of bilateral involvement were analysed too.

Audiological Phenotype of patients showing connexin 26/30 related deafness in a cohort including 628 patients.

CAMA, ELONA;SANTARELLI, ROSAMARIA;TOFFOLATTI, LUISA;INCOGNITO, ALESSANDRO;ARSLAN, EDOARDO
2008

Abstract

Mutations in the GJB2 gene are found to account for approximately 50% of cases of autosomal recessive non-syndromic deafness. A 342-kb deletion truncating the GJB6 gene has been associated with autosomal recessive non-syndromic deafness, mostly as digenic inheritance of the Cx30 deletion/Cx26 mutation. The following retrospective study describes audiological features and genotypes of a large cohort of 628 hearing impaired patients who underwent genetic screening for the GJB2/GJB6 genes and received follow-up care at our centre between January 2002 and July 2008. Mutations in GJB2/GJB6 genes were found in over than 30% of cases. Twenty-seven different genotypes causing deafness in more than 25% of patients with either biallelic mutations or digenic inheritance GJB2/GJB6 were identified. The most frequent mutations of the GJB2 were 35delG, L90P, M34T, delE120 and R184P. The 342-kb deletion del(GJB6-D13S1830) was also quite frequent. In more than 14% of cases the cause of deafness was the homozygosis for the most common mutation among European people the 35delG. Although more than 70% of patients with biallelic/digenic inheritance of the Cx30 deletion/Cx26 mutation exhibit a severe to profound hearing loss, mild and moderate impairment were also found. Other clinical data such as course and degree of bilateral involvement were analysed too.
IAPA 2008 - The XIV International Symposium in Audiolgoical Medicine
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2272405
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