Linkage Analysis for Four Genes (GPSM2, MSRB3, SLC26A5,GRXCR1) in 100 Iranian Families with Autosomal Recessive Hearing Loss

Hearing loss (HL) is the most frequent sensory defect present in 1 of every 500 newborns. In developed countries, at least 50% of cases are caused genetic factors, most often resulting in nonsyndromic HL (70%), which is usually autosomal recessive (80%). To date, fifty genes associated with autosomal recessive non-syndromic hearing loss (ARNSHL) have been reported.
The aim of this study was to determine the prevalence of mutations in four genes (GPSM2, MSRB3, SLC26A5, and GRXCR1) in Iranian deaf population with ARNSHL. These genes were mostly reported in our neighboring countries. One hundred unrelated Iranian families segregating ARNSHL with at least two affected siblings were subjected to our study.
We used homozygosity mapping to identify regions of autozygosity-by-descent using three flanking or intragenic short-tandem repeat (STR) markers for mentioned genes. If a family showed linked pattern to our selected STR markers, then direct sequencing was performed.
Seven families were linked to GPSM2, seventeen families were linked to GRXCR1, five families showed linkage to SLC26A5, and sixteen families linked to MSRB3. To confirm the mutation in linked families, direct sequencing was performed, however, after analyzing the sequencing results, no mutation could be detected in either of the families.
Our data showed that mutation in the studied genes, GPSM2, MSRB3, SLC26A5, and GRXCR1, is not prevalent in Iranian population.