And finally, although not analysed in all studies, in I-GS patients there is evidence of increased urinary presence of proteins larger than albumin (e.g. transferrin, IgG) that may not be fully explained exclusively by decreased tubular reabsorption, and whose presence in the primary filtrate could be consistent with mild SD dysfunction (Storm et al., 2013; Wahlstedt-Fröberg et al., 2003). Here, TF is linked to Salla disease.