Regarding the activity levels and concentrations of other VKDPs, like OC, which may be negatively influenced by vitamin K deficiency in PXE patients, Vanakker et al. [10] did not detect abnormal OC levels in PXE serum samples, while interestingly, OC levels seemed to be highly disturbed in IHC stained skin lesion biopsies from PXE patients compared to controls [10]. Here, BGLAP is linked to Pseudoxanthoma elasticum.