SummaryOtosclerosis is a condition characterized by an abnormal bone metabolism in the otic capsule, resulting in conductive and/or sensorineural hearing loss. Otosclerosis is a common disorder in which genes play an important role. Case-control association studies have implicated several genes in the abnormal bone metabolism associated with otosclerosis: COL1A1, TGFB1, BMP2, and BMP4. To investigate the association of these genes with otosclerosis in the Tunisian population, we examined nine single nucleotide polymorphisms (SNPs) in 159 unrelated otosclerosis patients and 155 unrelated controls. We found an association of rs11327935 in COL1A1 with otosclerosis that was shown to be sex specific. The coding polymorphism T263I in TGFB1 was also associated with otosclerosis in the Tunisian population. The effect sizes of both the associations were consistent with previous studies, as the same effect was found in all cases. The association of BMP2 and BMP4 was not significant. However, a trend towards association was found for the BMP4 gene that was consistent with earlier reports. In conclusion, this study replicates and strengthens the evidence for association between polymorphisms of COL1A1 and TGFB1 in the genetic aetiology of otosclerosis.

Level IIb or IV involvement is rare. Superselective neck dissection (IIa, III) seems to be indicated in T1T2 N0 tumor. In case of advanced tumor or pre-epiglottic space or cartilage invasion, functional neck dissection is mandatory.

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FOXE1 polyalanine tract (poly-Ala) has been associated with thyroid dysgenesis. Recently, the SNP (rs1867277:-238G>A) within the FOXE1 5'UTR was involved in the genetic susceptibility to thyroid cancer (TC). In the aim to assess the influence of FOXE1 poly-Ala length on the genetic susceptibility to TC and autoimmune thyroid diseases (AITD), a case-control design (including 261 Tunisian AITD, 170 Spanish TC and respectively 171 and 218 matched healthy subjects) was performed. The effect of Ala length and rs1867277 alleles on FOXE1 expression was investigated by mRNA relative real time quantification on 8 papillary thyroid carcinoma (PTC) and 10 Graves' disease (GD) genotyped thyroid biopsies. The fluorescent genotyping of poly-Ala polymorphism revealed nine alleles (from 12 to 22 repetitions). The association of poly-Ala polymorphism with AITD was rejected (Pc>0.05). However, a significant association was found with TC. In addition, the genotypic distributions revealed the predispositional effect of the 16/16 genotype (OR = 2.71; 95%CI: 1.36-5.42; p=0.001) and the protector effect of the 14/14 genotype (OR= 0.46; 95%CI: 0.29-0.72; p=0.003). The quantification studies reveal that FOXE1 transcripts were less abundant in PTC than GD samples. Moreover, FOXEI gene was 4,8 fold less expressed among PTC protected patients compared to homozygous 16/16-A/A. In conclusion, by exploring the poly-Ala polymorphism, we confirmed the involvement of {\it FOXE1} gene in the genetic susceptibility to TC and we reported its down expression among PTC tissues.

Recessive mutations of MYO15A are associated with nonsyndromic hearing loss (HL) in humans (DFNB3) and in the shaker-2 mouse. Human MYO15A has 66 exons and encodes unconventional myosin XVA. Analysis of 77 Tunisian consanguineous families segregating recessive deafness revealed evidence of linkage to microsatellite markers for DFNB3 in four families. In two families, sequencing of MYO15A led to the identification of two novel homozygous mutations: a nonsense (c.4998C>A (p.C1666X) in exon 17 and a splice site mutation in intron 54 (c.9229 + 1G>A). A novel mutation of unknown significance, c.7395 + 3G>C, was identified in the third family, and no mutation was found in the fourth family. In conclusion, we discovered three novel mutations of MYO15A, and our data suggest the possibility that there are two distinct genes at the DFNB3 locus.

Many studies suggest that the focal distribution of nasopharyngeal carcinoma (NPC) may be influenced not only by host genetics, diet and environments but also by interplay with Epstein-Barr virus (EBV) genetics. Specific EBV gene variants (the A and C types, the BamHI f configuration, a C terminal 30 bp deletion and a N terminal loss of an XhoI site in the BNLF1 gene) have been explored in high incidence areas in southern Asian NPC patients. In contrast, in Tunisia where NPC represents the most frequent type of Head and Neck cancer the distribution of these polymorphisms remains poorly investigated. In order to characterize the epidemiology of EBV variants in Tunisian NPC patients, we have investigated the A or B type of the EBV nuclear antigen (EBNA)2 gene, the C or D type of the BamHI W1/I1 region, the F/f variants of the BamHI F region and the presence or the absence of the XhoI site, 30 bp deletion and Taq1 site in the BNLF1 gene in 47 NPC biopsies, 12 being younger than 30 and 35 older than 30. Our results show a unique genetic profile of the tumor EBV strains regarding the A and D types, the prototype F and retention of the XhoI restriction site in the N terminal region of BNLF1 gene. With regard to the C terminal region of this gene, four genetic profiles were detected: (1) the occurrence of the 30 bp deletion in association with the Taq1 site in 39 cases (83%), (2) the presence of the Taq1 site by itself in 5 cases, (3) the occurrence of the 30 bp deletion by itself in 2 cases and (4) the occurrence of a new deletion of 81 bp covering the 30 bp deletion in association with the Taq1 site in one case. With the exception of the 81 bp deletion, which has not been previously described in the literature, the summarized results have shown the same genetic profile in Tunisian NPC tumor isolates as tumor isolates from other North African and Mediterranean countries. Hence, the observed EBV polymorphisms are not fully specific of to the Tunisian NPCs. Nevertheless, the notion of a divergence between North African and Asian tumor EBV isolates is reinforced by this study.

Down-expressed genes associated with DNA hypermethylation could be used as biomarkers for understanding complex pathogenic mechanisms underlying presbycusis.

Bupivacaine application is effective in decreasing postoperative pain and analgesic requirement during the hospital stay for patients with thyroidectomy.