IDUA and axial length measurement: Compellingly, however, IDUA is a lysosomal hydrolase responsible for the degradation of GAGs dermatan sulfate and heparan sulfate.41 An increased heparan sulfate has been found in amyloidosis.39 The increased presence of the PG DCN, combined with the decreased lysosomal hydrolase IDUA, indicates an increase in PGs and GAGs in ATTRwt-CM and AL-CM and a decrease in clearing, as supported by the up-regulated PG pathway in ATTRwt-CM and AL-CM found in this study.