A look at DFNB16 markers and their application in the genetic study of hearing loss in Iranian deaf families.

Introduction: The study of the gene encoding stereocilin (STRC) is complicated by the presence of a pseudogene (STRCP1) with over 98.8% similarity. We analysed the linkage between hearing loss and the DFNB16 locus in consanguineous Iranian deaf families.

Material and methods: A review of previous studies on the DFNB16 locus was conducted to find the smallest regions linked to the STRC gene with no reported crossing-overs, as well as an investigation of short tandem repeat (STR) and single nucleotide polymorphism (SNP) markers of the DFNB16 locus using the UCSC, NCBI, and Iranome databases. A total of 36 consanguineous families with at least two individuals affected by autosomal recessive non-syndromic hearing loss (ARNSHL) were selected for the study. Autozygosity mapping was performed using tag SNP markers linked to the DFNB16 locus.

Results: The investigation showed that SNPs are more appropriate for linkage studies in these families than STR markers. In this study 12 distinct haplotypes were identified, with frequencies ranging from 3.1% to 21.8%. Based on the haplotype analysis results and the autozygosity mapping, no linkage was found in any families analysed.

Discussion: In genetic studies of deafness in multi-affected consanguineous families, preliminary screening by autozygosity mapping can be helpful, especially for complicated genes like STRC. If the distance between STRs and the gene under study is significant, SNPs can provide a more effective solution. This study can potentially help to develop a more cost-effective method for genetic testing of STRC-related deafness.