Prevalence of mutations located at the dfnb1 locus in a population of cochlear implanted children in eastern Romania.

OBJECTIVE: Hearing loss is one of the major public health problems, with a genetic etiology in more than 60% of cases. Connexin 26 and connexin 30 mutations are the most prevalent causes of deafness. The aim of this study is to characterize and to establish the prevalence of the GJB2 and GJB6 gene mutations in a population of cochlear implanted recipients from Eastern Romania, this being the first report of this type in our country. METHODS: We present a retrospective study that enrolled 45 Caucasian cochlear implanted patients with non-syndromic sensorineural severe to profound, congenital or progressive with early-onset idiopathic hearing loss. We performed sequential analysis of exon 1 and the coding exon 2 of the GJB2 gene including also the splice sites and analysis of the deletions del(GJB6-D13S1830), del(GJB6-D13S1854) and del(chr13:19,837,343-19,968,698). RESULTS: The genetic analysis of the GJB2 gene identified connexin 26 mutations in 22 patients out of 45 (12 homozygous for c.35delG, 6 compound heterozygous and 4 with mutations only on one allele). We found 6 different mutations, the most prevalent being c.35delG - found on 32 alleles, followed by p.W24* - found on 2 alleles. We did not identify the deletions del(GJB6-D13S1830), del(GJB6-D13S1854) and del(chr13:19,837,343-19,968,698). CONCLUSIONS: Although the most prevalent mutation was c.35delG (80% from all types of mutations), unexpectedly we identified 5 more different mutations. The presence of 6 different mutations on the GJB2 gene has implications in hearing screening programs development in our region and in genetic counseling.

[Peripheral vestibular syndrome intricated pathogenic issues. A case report]. / Sindromul vestibular--aspecte patogenice intricate. Prezentare de caz.

BACKGROUND: Ménière's syndrome appears to be the final common pathway of the mechanisms the inner ear responds to almost any injury. Although the autoimmune disease seems to play a major role, exposure to intense noise can also be a trigger in the appearance and/or aggravation of the disease. MATERIAL AND METHODS: The case of 41 years old musician with a history of ankylosing spondylitis, diagnosed with Ménière's syndrome 5 years ago, is presented. Recently the symptoms became more polymorphic, revealing the association between benign paroxysmal positional vertigo (BPPV), Ménière's syndrome and high frequency hearing loss in an autoimmune background. Besides general, neurological and ENT examination, the diagnostic workup comprised of tonal audiogram, brain stem auditory evoked potentials, computerized dynamic posturography and videonistagmography. RESULTS: The final diagnosis was acute noise trauma, Ménière's syndrome, left horizontal semicircular canal BPPV, bilateral sensorineural sudden aggravated hearing loss in high frequencies (above 9 kHz) and allegedly autoimmune inner ear disease. Treatment with an association of corticosteroids, vasodilators and vitamins combined with Vannucchi's maneuver were followed by a significant relief of the symptoms. CONCLUSION: Although no causal relationship was found between acoustic trauma and increased endolymphatic pressure, both literature data and the case presented show that intense and prolonged noise exposure may aggravate peripheral vestibular syndrome.