title: A genotype-phenotype correlation in Sicilian patients with GJB2 biallelic mutations.
abstract: The aim of this work was to study the genotype distribution of Sicilian patients with biallelic GJB2 mutations; to correlate genotype classes and/or specific mutations of GJB2 gene (35delG-non-35delG) with audiologic profiles. A total of 10 different mutations and 11 different genotypes were evidenced in 73 SNHL subjects; 35delG (90.36 % of cases) and IVS1+1 (13.69 %) were the most common mutations found in the cohort with a significant difference in the distribution between North and South Sicily. Audiological evaluation revealed a severe (16/73) to profound (47/73) hearing loss (HL) in 86.13 % of cases without significant difference between the degree of HL and the province of origin of the subjects (P = 0.727). The homozygous truncating (T/T) genotype was the most widespread (89.04 % of cases), with a severe-to-profound hearing impairment in 90.36 % of T/T class with respect to truncating/non-truncating (T/NT) and non-truncating/non-truncating (NT/NT) genotypes (P = 0.012). From the comparison of homozygous 35delG and 35delG/non-35delG genotypes, a more profound HL in the homozygous 35delG than in compound heterozygous 35delG/non-35delG (p < 0.0001) resulted. This study confirms that 35delG is the most common mutation in the Mediterranean area with a heterogeneous distribution of the genotypes between North and South Sicily; probands homozygotes for 35delG or presenting a T/T genotype are more apt to have a severe-to-profound HL.
authors.affiliation: Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche (BioNeC), Sezione di Otorinolaringoiatria, Università degli Studi di Palermo, Via del Vespro, 129, 90127, Palermo, Italy, francescomartines@unipa.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Martines
authors.forename: Pietro
authors.initials: P
authors.lastname: Salvago
authors.forename: Caterina
authors.initials: C
authors.lastname: Bartolotta
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cocuzza
authors.forename: Carmelo
authors.initials: C
authors.lastname: Fabiano
authors.forename: Sergio
authors.initials: S
authors.lastname: Ferrara
authors.forename: Eleonora
authors.initials: E
authors.lastname: La Mattina
authors.forename: Marianna
authors.initials: M
authors.lastname: Mucia
authors.forename: Pietro
authors.initials: P
authors.lastname: Sammarco
authors.forename: Federico
authors.initials: F
authors.lastname: Sireci
authors.forename: Enrico
authors.initials: E
authors.lastname: Martines
mesh_terms: D001299:Audiometry / Q000379:methods; D002648:Child; D002675:Child, Preschool; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D003638:Deafness / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D005260:Female; D056726:Genetic Association Studies; D005838:Genotype; D034381:Hearing Loss / Q000235:genetics; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D008297:Male; D009154:Mutation; D012720:Severity of Illness Index; D012802:Sicily / Q000453:epidemiology; D055815:Young Adult
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26