Influence of pseudoxanthoma elasticum on the lipid profile and prognostic implications

Background: Pseudoxanthoma elasticum (PXE) is a rare, inherited disease characterised by specific skin lesions, progressive loss of vision and early onset atherosclerosis. Atherosclerosis in PXE leads to an increased rate of vascular occlusion and severe intermittent claudication. Although genetically determined, the individual course of PXE is highly variable. Up to now, there is no sufficient parameter to identify individuals at risk of rapid disease progression. This present study focused the lipid profile of patients with PXE and its possible influence on the clinical severity of peripheral artery disease (PAD). Patients and methods: 112 patients with PXE were retrospectively screened. Patients without a complete lipid profile consisting of total cholesterol (TC), triglycerides (TGC), high-density lipoprotein (HDL), low-density lipoprotein (LDL) and Lipoprotein(a) (Lp[a]) where excluded as well as patients with already initiated lipid-lowering therapy. 52 patients met the inclusion criteria. An age-adjusted ordinal regression model was applied to determine the association of each lipid fraction with the severity of PAD assessed as Fontaine classification. Results: The lipid profile of patients with PXE was unremarkable (TGC: 135.8±105.8 mg/dl; TC: 172.5±44.4 mg/dl; HDL: 63.0±18.2 mg/dl; Lp[a]: 64.7±93.5 nmol/l). Ordinal regression showed a significant association of Lp(a) with the severity of PAD with an odds ratio of 1.01 (1.00-1.02; p = 0.004), whereas the other fractions of the lipid profile had no significant influence. Conclusions: This study provides the largest evaluation of blood lipids up to now and the first characterization of Lp(a) levels in patients with PXE. We were able to provide first evidence of a correlation between elevated levels of Lp(a) and the severity of PAD. The present results suggest that determination of Lp(a) in early stages of PXE could help to identify patients at risk of rapid disease progression and with the need of intensified walking exercise training.