Large vestibular aqueduct (LVAD) is the most common inner ear anomaly, associated with sensorineural or mixed type of hearing impairment with varying degree and age of onset. LVAD is associated either with the hearing loss in Pendred syndrome (PDS) or in DFNB4, which are allellic disorders caused by mutations in SLC26A4 gene encoding iodide/chloride transporter, Pendrin. We ascertained a non-consanguineous Turkish family with three children having different types (sensorineural and mixed) and degrees (moderate, moderate-to-severe and profound) of hearing loss. CT scanning in the affecteds showed enlargement of vestibular aqueduct. The haplotype analysis with STR markers residing PDS/DFNB4 locus identified two haplotypes co-segregating with the LVAD syndrome in the form of compound heterozygosity. Mutation screening in the coding exons of SLC26A4 revealed that the affected sibs were compound heterozygous for previously described p.L445W and novel p.F515C mutations. p.L445W mutation is located in the sulfate transporter family domain and might be associated with thyroid goiter in homozygous state. The F515 residue is located in the eleventh transmembrane domain and was conserved along the evolution. Further clinical evaluation of the affected sibs and the frequency of p.F515C mutation in Turkish patients with non-syndromic hearing loss will be presented.