Biochemical analyses of macromolecular matrix components in patients with pseudoxanthoma elasticum

Two cases of pseudoxanthoma elasticum (PXE) were reported. Biochemical studies of collagen, glycosaminoglycan, and elastin content were performed using skin specimens from affected lesions. Hydroxyproline content was reduced approximately 46% and 24% in cases 1 and 2, respectively. The reduction in collagen content resulted from the reduction in the lower dermis, not from that in the upper dermis. Glycosaminoglycan content in PXE was also decreased, with a slight increase in the ratio of hyaluronic acid to dermatan sulfate. Isodesmosine content in PXE was increased 3.2- and 2.2-fold in cases 1 and 2, respectively. These results suggest that the major and primary biochemical changes in PXE are an increase in elastin content.