Mutations in GJB2, a gene encoding the gap junction protein connexin 26 (Cx26), are a major cause for inherited and sporadic non-syndromic hearing loss, albeit with highly variable clinical effects. To determine new mutations and their frequencies in a Southern Egyptian population restriction fragment length polymorphism, gene sequencing, and single strand conformational polymorphism revealed only 2 mutations for GJB2: c.35delG and p.I71N. The allelic frequency of the c.35delG mutation was 8.7% (found in 27 out of 310 investigated alleles) resulting in a relatively low carrier frequency (1.6%) in Upper Egypt. The new mutation, a substitution of isoleucin (I) (a non-polar amino acid) by the polar amino acid asparagin (N), was localized within the conserved Cx26 structure. The functional significance of p.I71N was tested by injection of cRNA into Xenopus laevis oocytes. Cx26 hemi-channel activity was measured by depolarization activated conductance in non-coupled oocytes. As a result, the p.I71N mutated channel was non-functional. The study discloses a novel, functionally relevant GJB2 mutation and defines the contribution of Cx26 alterations to the hearing loss in the Southern Egyptian population.

The study was aimed at finding what factors in evoked potentials and EEG related to stuttering in subjects 6–25 years of age. Thirty-seven subjects who stuttered and 25 nonstuttering subjects, matched for age, sex and education, were evaluated employing visual evoked potentials, auditory evoked potentials, event-related potentials (P₃₀₀), WISC-(IQ), and electroencephalography. A significant reduction of amplitude of P₁₀₀ of visual evoked potentials was found in stutterers with a significant prolongation of wave latencies I, III, V and interpeak latencies I–III and I–V in brainstem auditory evoked potentials. No significant abnormalities were recorded in P₂₀₀, N₂₀₀ and P₃₀₀ of event-related potentials in stutterers compared with the control group. The dominant EEG rhythm was slower in stutterers with a significant interhemispheric asymmetry compared with the control group. Fifty-four percent of the stutterers had pathological EEG. Epileptiform activities were recorded in 16.2% of stuttering subjects. Focal left temporal spike activity was recorded in 5.4% of stuttering subjects. The findings of this study point to a possible role of an organic etiopathogenesis of stuttering.

Background: Combined hearing and vestibular loss in children pose potentially significant problems. Children and infants with vestibular problems are faced with motor problems that could limit their normal development. Objectives: the aim of the study is to assess the relationship between the vestibular disorders and the delayed motor development in hearing impaired children as well as to assess the integrity of the vestibular system through clinical testing and radiological imaging in those children with delayed motor development. Methods: Thirty hearing impaired children with history of delayed motor milestones, and a control group of 10 hearing impaired children with normal motor development were included with variable degree of hearing loss. Each child was subjected to careful history taking, general examination, otoscopic examination, motor and balance questionnaires were answered by the parents or caregivers, audiological evaluation either through conditioned play audiometry or conventional audiometry, speech audiometry and Immittancemetry. Vestibular evaluation through cVEMP and caloric tests and finally the radiological studies through CT and MRI of the petrous bone. Results: There were variable degrees of hearing loss among both groups. In the control group (10 HI children, 20 ears), 18 ears (90%) had VEMP response, while two ears (10%) had absent VEMP, while in the study group (30 HI children, 60 ears), 48 ears (80%) had VEMP response, while 12 ears (20%) had absent VEMP. All children in the control group had normal caloric response, while in the study group, 23 children (77%) had normal response, and seven children (23%) had abnormal caloric response, 4 children had bilateral weakness and 3 had unilateral weakness. CT and MRI study of petrous bone was done for the control group and revealed normal radiology, while in the study group, 21 children had normal imaging (70%) and the last 9 children (30%) had abnormal findings, the most common abnormalities was enlarged vestibular aqueduct (13%), followed by common cavity (7%). Conclusion: Children with hearing loss, irrespective of the degree of hearing loss, the vestibular system should be screened, assessed as it may be responsible for co-morbidities in fine and gross motor difficulties. Early intervention and effective therapy will be the proper way to get good outcome.

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