Although etiologically heterogeneous at least 50% of all early on-set hearing losses have a genetic cause and of these, the large majority, 75-80% are most probably autosomal recessive and 70% are non-syndromic. The rest of the congenital hearing losses are determined by clinical and environmental factors such as ototoxic medication, prematurity, and complications at birth. During the last decade it became clear that 50-80% of all such afflictions result from mutations in a single gene, GJB2, which encodes the protein Connexin 26. In order to, at least partially clarify this problem, especially in an emerging country such as Romania, where the problem is not studied adequately, we developed a comprehensive study of genetic, clinical and environmental risk factors for congenital hearing loss. The two most common variations of this gene, 35delG and W24X in children with positive diagnosis of bilateral severe to profound sensorineural hearing loss were investigated. A cohort of 34 children (20 female and 14 male), ages between 2 and 10 (mean age 4.62 years), coming from 33 non-related families were evaluated. All cases were diagnosed with severe or profound bilateral congenital SNHL. A statistical comparison of genetic and environmental/clinical prevalence was also attempted since the presence of a genetic disorder cannot rule out the role of other documented risk factors in the etiology of SNHL. The results showed that, 29.4% of cases (10/34) were homozygotic for the 35delG mutation 35delG/35delG), also known as genotype Δ/Δ. 5.88% of cases (2/34) belong to the heterozygotic bi-genic group 35delG/W24X. The clinical factors with high statistical significance for SNHL in a non-genetic group have no significance for genetic SNHL patients. Thus, the present study confirms the relatively high prevalence of the 35delG and W24X mutations in cases of congenital non-syndromic severe of profound bilateral SNHL.

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A long-term, retrospective, non-controlled study was performed on the drainage results of mastoidectomy (both radical and modified radical) and the relevant statistical factors that could influence the anatomic outcome were defined. The present study took into consideration the same cohort of 200 patients we have communicated with before in our previous studies concerning the long-term functional results of mastoidectomy and long-term results of ossicular replacement with biovitroceramic prosthesis. The patients were clinically followed for the same period of 8.12 years. The drainage (anatomic) results, similar to previously published functional results, were defined by analytical function of the severity and the period of evolution of disease. The main goal was to define the situations and factors (presence of complications, type of disease, type of tympanic perforation or status of ossicular chain) that influenced the drainage results that could provide us with some type of anatomical prognosis. The follow-up started at the moment of complete epithelization for each cavity as time represents the main study comparison criteria. Drainage failure was assessed by the number of otorrhea episodes. It was concluded that practically and ideally, a maximum of 84% of the mastoid and petrous cells can be cleaned out. The results of 78% drainage success are congruent to this theory. The remaining 16% of cells may contain irreversible lesions.