This monocentric clinical observational study at the University Eye Hospital Bonn investigates the natural history and structural consequences of a diseased Bruch's membrane (BrM) in Pseudoxanthoma elasticum (PXE). The study includes four main objectives:

1. Direct Bruch's Membrane Alterations: Longitudinal analysis of BrM reflectivity using high-resolution OCT to assess correlations with disease progression
2. Choriocapillaris Flow Deficits: Evaluation of choriocapillaris (CC) perfusion in relation to BrM calcification, aiming to clarify whether CC deficits precede or result from BrM changes
3. Retinal Atrophy Progression: Monitoring the development and expansion of retinal atrophic areas over two years, including correlations with specific features like reticular pseudodrusen and hyperreflective spots
4. Genotype-Phenotype Correlation: Analysis of different ABCC6 gene mutations to identify correlations with imaging features and disease severity, potentially guiding future personalized therapeutic strategies

The study will recruit 100 PXE patients and 100 controls, with data collection over 10 years. It involves non-invasive imaging and blood sampling. No direct benefit is expected for participants, but the findings may inform future clinical trials and improve patient counseling.

Inclusion Criteria for PXE cohort:

• PXE based on the criteria of Plomp et al.
• Clear ocular media
• Ability to perform the tasks of the study protocol (i.e., holding the head still for image aquisition)

Exclusion Criteria:

• Any confounding ocular disease not associated with PXE
• Systemic diseases hindering the study examinations

PXE patients will be recruited from the dedicated PXE clinic in Bonn, Germany and is open for any PXE patient (external clinics) that desire to participate.

We will also present the study at the Annual meeting of the German PXE patient organization and with PXE international, the largest patient organization worldwide.