A deletion of at least 140 kb starting approximately 35kb upstream (telomeric) to the GJB2 (CX26) gene was identified in 7 patients from 4 unrelated Jewish Ashkenazi families with non-syndromic hearing loss. These patients were heterozygous for one of the common mutations 167delT or 35delG in the GJB2 gene in trans to the deletion. The deletion started at 5' side of the GJB6 (CX30) gene including the first exon and it did not affect the integrity of the GJB2 gene. The deletion mutation segregated together with the hearing loss, and was not found in a control group of 100 Ashkenazi individuals. We suggest that the deletion is a recessive mutation causing hearing loss in individuals that are double heterozygous for the deletion and for a mutation in the GJB2 gene. The effect of the deletion mutation could be due to a digenic mode of inheritance of GJB2 and GJB6 genes that encode two different connexins; connexin 26 and connexin 30, or it may abolish control elements that are important in the expression of the GJB2 gene in the cochlea. Regardless which of the options is valid, it is apparent that the deletion mutation provides a new insight into connexin function in the auditory system. The deletion mutation was on the same haplotypic background in all the families, and therefore is a founder mutation that increases the impact of GJB2 in the etiology of prelingual recessive non-syndromic hearing loss in the Ashkenazi population.

Twenty-seven unrelated Jewish Ashkenazi patients with nonsyndromic prelingual deafness (NSD) were analyzed for mutations in the coding sequence of the connexin 26 (Cx26) gene. Biallelic mutations were identified in 19 of the 27 patients (70.4%); 12 were homozygous for the mutation 167delT, 2 were homozygous for the mutation 35delG, and 5 were compound 167delT/35delG heterozygotes. In addition three patients were heterozygous with no second identified mutation in the Cx26 gene. Biallelic mutations in the Cx26 gene account for 83% of familial cases and 44% of the sporadic cases. Among 268 unselected Ashkenazi individuals, 20 were 167delT/N heterozygotes, giving an estimate of 7.5% carrier frequency. Based on the 167delT carrier frequency in three studies (including the present one), it is expected that 167delT/167delT homozygotes account for 70% of all patients with NSD (1 in 1300). The hearing capacity of 30 patients (probands and their sibs) with biallelic Cx26 mutations and at least one allele with 167delT demonstrated inter- and intrafamilial variability from profound to mild hearing impairment.

Thirty-five patients with Behçet's disease (20 under cyclosporine A [CyA] treatment and 15 under the conventional therapy), 12 patients suffering from endogenous uveitis, and 35 normal subjects were evaluated audiologically before entering the study and were followed up for at least a year. Twenty-eight Behçet patients (80%) showed some degree of hearing loss. The averaged pure tone audiogram of the Behçet group showed statistically significant auditory deficits in comparison with that of the control group. None of either the Behçet group or the uveitis group showed any hearing deterioration during the follow-up period. Five Behçet patients under CyA therapy demonstrated improvement in their hearing. The difference between the two groups of Behçet patients (CyA versus conventional treatment) was found to be statistically significant (p less than .05). Thus, CyA might serve as an important mode of treatment of sensorineural hearing loss on an inflammatory "autoimmune" background.

The recent discoveries of genes involved in deafness open new options for families and individuals with hearing loss. Our aim was to learn if parents of children with hearing loss will benefit from these new possibilities. A total of 139 parents answered questionnaires aimed at evaluating their intentions as well as their reasons to opt for or against genetic testing and prenatal diagnosis for hearing loss. A very high interest (87%) in genetic testing was found among Israeli Jewish parents of deaf and hard-of-hearing children. Although the Jewish population in Israel is very diverse in its religious beliefs, this high interest was similar across all religious sectors (secular, traditional, orthodox, and ultraorthodox); however, some of the reasons for undertaking such a test were very different between them. Reasons related to family planning and prenatal diagnosis were significantly less important to parents from the ultraorthodox sector, but the possibility to utilize genetic testing for matchmaking the children with hearing loss and their hearing siblings was an important factor in motivating them to undertake the test. Parents from all religious sectors wished testing would shed light on the cause of the hearing loss. We conclude that genetic testing would be welcomed by a wide range of communities, including those that usually do not apply for genetic counseling and testing, if it is offered in accordance with their cultural norms and beliefs.

To perform chromosomal mapping and clinical analysis of hereditary otosclerosis linked to the fourth locus for otosclerosis (OTSC4) in an Israeli family.