Dossena et al. (2011) performed functional analysis to characterize of the ion transport activity of three pendrin mutations that Walsh et al. (2006) previously found in deaf Palestinian patients with EVA. Results indicated that both the Cl(-)/I(-) and the Cl(-)/OH(-) exchange activities of pendrin V239D and G334V X335 mutations were significantly reduced with respect to the wild type, with V239D displaying a residual iodide transport. Dossena et al. (2011) postulated that the residual function displayed by the V239D mutation could lead to the amelioration of the symptoms caused by this mutation due to a pendrin 'activator'.

To evaluate the contribution of the PDS gene (SLC26A4) in the genetic susceptibility of autoimmune thyroid disease (AITD), Hadj Kacem et al. (2003) examined 4 microsatellite markers in the gene region. They genotyped 233 unrelated AITD patients, 15 multiplex AITD families, and 154 normal controls. Analysis of case-control data showed a significant association of D7S496 and D7S2459 with Graves disease and Hashimoto thyroiditis, respectively. The family-based association test showed significant association and linkage between AITDs and alleles 121 bp of D7S496 and 173 bp of D7S501. Results obtained by transmission disequilibrium test were in good agreement with those obtained by the family-based association test. Indeed, evidence for linkage and association of allele 121 bp of D7S496 with AITD was confirmed (P = 0.0114). The authors concluded that SLC26A4 should be considered a susceptibility gene to AITDs with varying contributions in each pathology.