Identification of two heterozygous mutations in the SLC26A4/PDS gene in a family with Pendred-syndrome

Background: Pendred-syndrome is an autosomal recessive disease that is classically characterised by sensorineural hearing loss and enlargement of the thyroid gland. The gene SLC26A4/PDS for the pendred-syndrome has been localised by linkage analysis on chromosome 7q31. This protein is expressed in the inner ear, thyroid gland, kidney and placenta. Functional analysis in Xenopus laevis oocytes revealed that it acts as an iodide/chloride and chloride/formate exchanger. Method: Each of the exons and flanking splice regions of the SLC26A4/PDS gene was analysed by direct sequencing. Results: In the involved family two heterozygous mutations could be detected which results by combination in hearing loss and deafness. Conclusion: By evidences of familial background in hearing loss and thyroid disorder it is reasonable to analyse the PDS gene for mutation to have early the possibility for medical care of linguistic development through hearing aid or CI-implantation.