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.
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.