The Study of SLC26A4 Gene Causing Autosomal Recessive Hearing Loss by Linkage Analysis in a Cohort of Iranian Populations

Document Type : Original Article

Authors
Somayeh Reiisi 1
Mohammad Hosein Sanati 1
Mohammad Amin Tabatabaiefar 2
Shahla Ahmadian 3
Salimeh Reiisi 4
Shahrbanoo Parchami 3
Hamid Porjafari 5
Heshmat Shahi 1
Afsaneh Shavarzi 3
Morteza Hashemzade Chaleshtori 3
1 Medical Genetics Department, National Institute of Genetic Engineering and Biotechnology (NIGEB)
2 Medical Genetics Department, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
3 Cellular and Molecular Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran
4 Biochemistry Department, Maleke-Ashtar University of Technology, Tehran Iran
5 Medical Genetics Department, Hamedan University of Medical Sciences, Hamedan, Iran
Abstract
Sensorineural non-syndromic hearing loss is the most common disorder which affects 1 in 500 newborns.
Hearing loss is an extremely heterogeneous defect with more than 100 loci identified to date. According to the
studies, mutations in GJB2 are estimated to be involved in 50- 80% of autosomal recessive non-syndromic
hearing loss cases, but contribution of other loci in this disorder is yet ambiguous. With regard to studies,
DFNB4 locus (SLC26A4) can be classified as the second cause of hearing loss. So, this study aimed to determine
the contribution of this locus in hearing loss as well as the frequency of SLC26A4 gene mutations in a
population in the west of Iran. In this descriptive laboratory study, we included 30 families from the west of Iran
with no mutation in GJB2 gene. Linkage analysis was performed by DFNB4 (SLC26A4) molecular markers
(STR). The families with hearing loss linked to this locus were further analyzed for mutation detection.
SLC26A4 gene exons were amplified and analyzed using direct DNA sequencing. In studied families, 2 families
displayed linkage to DFNB4 locus. Identified mutations include mutation in exon 5 (c.416 G>T) and in splicing
site of exon 7 (IVS-2 A>G or c.919-2 A>G).
Keywords
SLC26A4
hearing loss
linkage analysis
Iran