Figure 1. Peripheral vascular aging in pseudoxanthoma elasticum: mutations in the ABCC6 gene on chromosome 16 (1), which encodes the ABCC6 transporter, result in low levels of inorganic pyrophosphate, a strong inhibitor of ectopic calcification (2). The subsequent peripheral artery calcification in the carotid siphon (3A, white arrows) results in lacunar infarctions (4A, red arrow) and white matter lesions (4A, blue arrows). Calcification of the femoral arteries (3B) results in peripheral arterial disease (PAD). 4B shows decreased ankle brachial index (ABI) of the left (blue line) and right (red line) leg after treadmill test, diagnostic for PAD.