Identification of two different mutations in the PDS gene in an inbred family with Pendred syndrome

Recently the gene responsible for Pendred syndrome (PDS) was isolated and s everal mutations in the PDS gene have been identified in Pendred patients. Here we report the occurrence of two different PDS mutations in an extended inbred Turkish family. The majority of patients in this family are homozyg ous for a splice site mutation (1143-2A-->G) affecting the 3' splice site c onsensus sequence of intron 7. However, two affected sibs with nonconsangui neous parents are compound heterozygotes for the splice site mutation and a missense mutation (1558T-->G), substituting an evolutionarily conserved am ino acid. The latter mutation has been found previously in two Pendred fami lies originating from The Netherlands, indicating that the 1558T-->G mutati on may be a common mutation.