الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Hearing loss has a significant impact on childhood development and integration into society. Around 1 to 6 children out of every 1,000 are born with severe to profound sensory neural hearing loss. (1-6)
These children are candidates for cochlear implant, a well-established safe method for rehabilitation of hearing. However, in settings where children get the same educational programs following cochlear implant at a similar age, substantial differences in auditory performance persist that are not attributed to implantation age or training quantity.(3, 7-9)
Autosomal recessive non-syndromic hearing loss is the most common cause of genetic deafness. (10-12) To date, more than 120 genes have been revealed to be involved in non-syndromic hearing loss. (13) Among them, the most common causative gene is gap junction beta 2, which encodes connexin 26 protein. (10, 11, 14)
In numerous papers, cochlear implant results in children with gap junction beta 2-related hearing loss were variable and in general inconclusive and controversial. (3, 7, 8, 15, 16) In some studies, it has even been indicated that carrying GJB2 mutation is associated with poorer cochlear implant outcomes.(7, 15) To date, this correlation has not been thoroughly investigated among Egyptian patient with SNHL and treated with cochlear implant.
The aim of this work is to analyze the coding region of gap junction beta 2 among cochlear implant recipients in Alexandria University Hospitals and to evaluate performance of cochlear implant recipients in relation to gap junction beta 2 gene mutations.
The study included thirty patients from three Egyptian governorates in the country’s northeastern region who were treated at Alexandria University Hospitals.
The case cohort presented with prelingual onset of bilateral severe to profound non syndromic sensory neural hearing loss. They had cochlear implant surgery before age of 5 year. Pedigrees of them showed autosomal recessive pattern of inheritance. Audiologic evaluation suitable for each patient according to their age and speech development was performed and gap junction beta 2 sequencing analysis was undertaken.