Here we studied for the first time the expression, localization, and targeting of the wild-type sialin as well as two mutant polypeptides; one mimicking the Finnish founder mutation, R39C (Salla(FIN)), and the other a deletion (del268-272) found in ISSD patients using in vitro expression of the corresponding cDNA constructs.
We found a homozygous SLC17A5 mutation (R39C) in five Finnish patients with Salla disease and six different SLC17A5 mutations in six ISSD patients of different ethnic origins.