APCS and autosomal dominant polycystic kidney disease: While the fact that the majority of proteins does not reach a significant correlation with eGFR in the IgAN cohort may be a consequence of limited cohort size, it is important to note, that many of these proteins are indeed far from the significance threshold and partly even show opposite directions of correlation compared to ADPKD (e.g. APCS, SERPINA6, SERPINF1 or PCOLCE).