Molecular diagnosis of autosomal recessive non-syndromic hearing losses

Year 2012, , 45 - 50, 01.05.2012

Zeynep Ocak Abdulgani Tatar Ahmet Yesilyurt Sıtkı Oztas

https://doi.org/10.5505/abantmedj.2012.02486

Abstract

OBJECTIVE: The aim of this study was to investigate the auditory disorders in or around Erzurum from the genetic aspects, to determine GJB2 gene mutations that lead to non-syndromic autosomal recessive hearing loss and to determine mutation profile for this gene. METHODS: 50 patients with hearing loss and 50 healthy volunteers participated to this study. Patients whose examination and auditory tests were performed at the ear-nose-throat outpatient clinics were referred to us to be evaluated for an underlying syndrome. GJB2 gene was amplified with polymerase chain reaction PCR after DNA extraction and presence of 35delG, 235delC, 167delT, 176-191del16, V95M and W77X mutations were investigated by using PCR-SSCP and RFLP techniques.RESULTS: As a result of the GJB2 gene studies of the 50 patients in the study group, 35delG mutation was detected in 10 patients 7 homozygous and 3 heterozygous . Of these 7 patients with homozygous mutations, we could reach the parents of 2 patients and heterozygous 35de1G mutation was detected in these. Among the 50 healthy control subjects, a heterozygous 35de1G mutation was detected in 1 patient and this patient was given genetic counseling. The other mutations that belong to GJB2 gene V95M, 176-191Del16, 235DelC, 167DelT, W77X were not detected in either of the groups. CONCLUSION: As a result of our study, GJB2 gene mutations were detected to be an important etiological factor in patients with autosomal recessive hearing disorders residing in or around Erzurum.

Keywords

GJB2, Non-sendromic hearing loss, SSCP

Otozomal Resesif Non-Sendromik İşitme Kayıplarının Moleküler Tanısı

Abstract

AMAÇ: Bu çalışmada, Erzurum ili ve çevresinde işitme bozukluklarının genetik yönden araştırılması, non-sendromik otozomal resesif işitme kaybına neden olan GJB2 gen mutasyonların belirlenmesi ve mutasyon profilinin çıkartılması amaçlanmıştır. YÖNTEMLER: Bu çalışmaya 50 işitme kayıplı hasta ve 50 sağlıklı gönüllü alınmıştır. KBB servisinde muayene ve işitme testleri yapılan hastalar, sendromik açıdan bölümümüzde değerlendirilmiştir. DNA ekstraksiyonunu takiben GJB2 geni Polimeraz zincir reaksiyonu PCR ile amplifiye edilmiş ve PCR-SSCP ve RFLP teknikleri kullanılarak; 35delG, 235delC, 167delT, 176-191del16, V95M ve W77X mutasyonlarının varlığı araştırılmıştır. BULGULAR: Çalışma grubumuzu oluşturan 50 hastanın GJB2 gen incelemesinde 10 hastada 7 homozigot ve 3 heterozigot 35delG mutasyonu tespit edilmiştir. Bu 7 homozigot hastanın ulaşabildiğimiz iki tanesinin ebeveyninde heterozigot 35delG mutasyonu saptanmıştır. Çalışılan 50 sağlıklı kontrolün bir tanesinde heterozigot 35delG mutasyonu saptanmış olup, genetik danışmanlık verilmiştir. GJB2 genine ait diğer mutasyonlar V95M, 176-191Del16, 235DelC, 167DelT, W77X çalışılan her iki grupta da tespit edilememiştir.SONUÇ: Çalışmamızın sonucunda Erzurumbölgesinde GJB2 gen mutasyonlarının non-sendromik otozomal resesif işitme kaybı olan bireylerde hastalığın etiyolojisinde önemli bir neden olduğu saptanmıştır.

Keywords

GJB2, Non-sendromik işitme kaybı, SSCP

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