The Prevention of Systemic Ectopic Mineralization in Pseudoxanthoma Elasticum
The goal of this randomized clinical trial is to assess the effect of etidronate on ectopic calcification in relatively young patients with Pseudoxanthoma elasticum. The main question it aims to answer are: What is the difference in the arterial calcification scores in the legs and the carotid syphon measured on low-dose CT scan after 24 months of treatment compared to baseline between etidronate and placebo. Participants will be asked to do take etidronate or placebo for 24 months.
⁃ In order to be eligible to participate in this study, a subject must meet all of the following criteria:
• 1\. Be between 18 years and 50 years.
• 2\. Have a definitive diagnosis of PXE according to the Plomp criteria, which confirm a diagnosis of PXE when at least two (or more) criteria not belonging to the same category (skin, eye, genetic) are met:
‣ Skin
• Yellowish papules and/or plaques on the lateral side of the neck and/or flexural areas of the body or
∙ Increase of morphologically altered elastin with fragmentation, clumping and calcification of elastic fibers in a skin biopsy taken.
⁃ Eye
• Peau d'orange of the retina or
∙ One or more angioid streaks (AS), each at least as long as one disk diameter. When in doubt, fluorescein or indocyanine green angiography of the fundus is needed for confirmation.
⁃ Genetics
• A pathogenic mutation of both alleles of the ABCC6 gene or
∙ A first-degree relative (parent, sibling or child) who meets independently the diagnostic criteria for definitive PXE
• 3\. Fertile women must take adequate anticonception.