ABCC6 and pseudoxanthoma elasticum (inherited or acquired): The mutation R1314Q, which also gave rise to a partially mislocalized ABCC6 protein, was found in a PXE patient with 0.35 ± 0.03 μM plasma PPi concentration, and one who, in contrast, had 0.7 ± 0.04 μM of plasma PPi (Figure 3E, right panel).