Lysosomal enzyme involved in the degradation pathway of dermatan sulfate and heparan sulfate. {ECO:0000269|PubMed:10838181, ECO:0000269|PubMed:11731225, ECO:0000269|PubMed:28593992}. This is the function of IDS (iduronate 2-sulfatase, ENSG00000010404).