Pseudoxanthoma Elasticum (PXE) Natural History Biomarkers in PXE Individuals and Their Biological Non-PXE Siblings

An Evaluation of Pseudoxanthoma Elasticum (PXE) Natural History Biomarkers in PXE Individuals and Their Biological Non-PXE Siblings

This PXE biomarker study aims to characterize the levels of inorganic pyrophosphate (PPi), pyridoxal 5´-phosphate (PLP), and other biomarkers relevant to PXE and ectopic calcification in both PXE patients and their biological siblings who are PXE carriers or normal non-PXE individuals.

This non-interventional PXE study is designed to assess differences in circulation levels of selective biomarkers related to PXE and tissue-nonspecific alkaline phosphatase (TNAP) inhibition, between PXE patients, PXE carriers, and non-PXE normal individuals.

Inclusion Criteria:

• Male or female participants aged 18 to 75 years

• Participants (approximately 1 carrier and 1 normal to match proband)

  • Confirmed PXE participants: index PXE/proband with established PXE and ABCC6 mutations identified
  • PXE carrier participants: biological sibling of the PXE index case and confirmed as PXE carrier
  • Non-PXE normal participants: biological sibling of PXE index case and confirmed as non-PXE normal

Exclusion Criteria:

• Unconfirmed ABCC6 mutation status
• Use of bisphosphonate in the preceding 12 months and during the study
• Use of Vitamin B6 and/or Vitamin D supplement in the preceding 1 month and during the study (if the total Vitamin B6 supplementation is >5 mg/day)
• Recent initiation or dose change of Vitamin D and/or multivitamin supplement in the preceding 1 month and during the study
• Bone fracture within 3 months prior to Screening or active bone disease (excluding osteopenia or osteoporosis)
• History of hyperparathyroidism
• History of moderate to severe renal impairment
• History of hypophosphatasia
• Known history of uncorrected abnormality in calcium (Ca), phosphate, alkaline phosphatase (ALP) or parathyroid hormone
• Other significant condition (medical, psychiatric, social, or medication) that, in the judgment of the Investigator, would prevent full participation or would be inappropriate for the study