A male patient with pseudoxanthoma elasticum caused by isodisomy of chromosome 16 containing a nonsense variant of the ABCC6 gene: A quarter-century treatment experience

Pseudoxanthoma elasticum (PXE) is a rare autosomal recessive disorder characterized by fragmentation and calcification of the elastic fibers of the skin, eyes, and various arteries with highly variable clinical expression. PXE is predominantly caused by pathogenic variants of the ABCC6 gene, which encodes the ABCC6 efflux transporter; however, the precise mechanism responsible for clinical manifestation remains unclear. We herein report the case of a male patient with PXE with premature coronary stenosis as his first presentation requiring catheter intervention, in association with typical ocular and skin lesions; the latter was confirmed histologically. A molecular analysis revealed an isodisomy of 6.8 Mb in the 16p13.11 region containing the nonsense mutation p.(Gln199Ter) in the ABCC6 gene. We also describe the 25-year clinical course of this case, while focusing on cardiovascular lesions.