Mutation analysis of the GJB2 and GJB6 genes in Egyptian patients with autosomal recessive sensorineural nonsyndromic hearing loss

Elbagoury, Nagham M.a; Soliman, Hala N.a; Mohammed, Ola S.c; Ghorab, Eman A.d; Elruby, Mona O.b; El-bassyouni, Hala T.b; Essawi, Mona L.a

Middle East Journal of Medical Genetics: January 2014 - Volume 3 - Issue 1 - p 11–15
doi: 10.1097/01.MXE.0000438176.01557.b9
Original articles

Background: Autosomal recessive nonsyndromic hearing loss (ARNSHL) is the most common type of hereditary hearing loss. It is extremely heterogeneous and over 70 loci (known as DFNB) have been identified. The most frequent gene implicated in ARNSHL is GJB2, which is responsible for more than half of the cases. It is located in the DFNB1 locus, which contains the GJB2 and GJB6 genes.

Aim of the study: The aim of the study was to detect the frequency of mutations in the GJB2 gene and the two most common deletions in the GJB6 gene [Del (GJB6-D13S1830) and del (GJB6-D13S1854)] in 36 Egyptian patients diagnosed with congenital, nonsyndromic hearing loss.

Patients and methods: Thirty-six patients with congenital, nonsyndromic hearing loss included in the study were sequenced for the exon 2 in GJB2. Multiplex PCR to detect del (GJB6-D13S1830) and del (GJB6-D13S1854) was performed.

Results: Five patients had the c.35delG mutation in the homozygous form (62.5%) and three patients had the mutation in the heterozygous form (37.5%). No deletions were detected in GJB6 among the studied patients.

Conclusion and recommendations: The c.35delG mutation is the most common GJB2 mutation among the studied patients. Further studies on other genes involved in the development of ARNSHL are warranted. Cohort study on the Egyptians for detection of the carrier rate is recommended.

Departments of aMedical Molecular Genetics

bClinical Genetics, National Research Centre, Division of Human Genetics and Genome Research

cDepartment of Biochemistry, Faculty of Pharmacy for Girls, Al-Azhar University, Cairo

dAudiology Unit, Giza, Hearing and Speech Institute, Egypt

Correspondence to Nagham M. Elbagoury, Department of Medical Molecular Genetics, National Research Centre, Division of Human Genetics and Genome Research, 33 El-Buhouth St Dokki, Giza 12622, Egypt Tel: +20 122 382 3604; fax: +20 33354791; e-mail:

Received April 28, 2013

Accepted October 8, 2013

© 2014 Middle East Journal of Medical Genetics