Background: Systemic lupus erythematosus (SLE) is an autoimmune disorder associated with premature atherosclerosis and vascular impairment. However, the role of endocan, a biomarker of glycocalyx injury, is not completely clarified in the detection of vascular damage. Therefore, our aim was to investigate serum endocan in comparison with conventional inflammatory markers, arterial stiffness parameters, and carotid ultrasound findings in a cohort of young patients with SLE. Methods: We enrolled 47 clinically active young SLE patients (40 females and 7 males) in the study. Arterial stiffness indicated by augmentation index and pulse wave velocity (PWV) was measured by arteriography. Brachial artery flow-mediated dilatation and common carotid intima-media thickness were detected by ultrasonography. The serum concentrations of endocan, IL-6, MPO, MCP-1, MMP-3, -7, and -9, as well as TNFα, were measured by an enzyme-linked immunosorbent assay (ELISA). Results: We found significant negative correlations between serum endocan and both CH50 and C3. Serum endocan was higher in active SLE patients compared to inactive patients, however, the difference was not statistically significant (241.4 (183–295) vs. 200.3 (167–278) pg/mL; p = 0.313). Serum TNFα and hsCRP significantly correlated with PWV. However, we did not detect significant correlations between vascular diagnostic tests and serum endocan levels. Conclusions: Based on our results, serum endocan is associated with disease activity; however, further studies are needed to clarify the value of serum endocan in the cardiovascular risk estimation of SLE patients. Measurement of serum endocan, as well as the routine assessment of arterial stiffness parameters, should be integrated into the comprehensive management plans of young patients with SLE.

Background/Objectives: The clinical presentation of homozygous familial hypercholesterolemia (HoFH) and severe heterozygous familial hypercholesterolemia (sHeFH) often demonstrates substantial overlap, as low-density lipoprotein cholesterol (LDL-C) levels may fall within similar ranges in both conditions. Methods: In this single-center 10-year retrospective study at the University of Debrecen, Hungary, we present the clinical characteristics of patients with 6 HoFH and 6 sHeFH diagnosed by genetic testing, discuss the diagnostic limitations encountered in clinical practice, and outline the key components of therapeutic management. Results: The mean age at diagnosis was lower in the HoFH group (31.83 ± 19.5 vs. 41.83 ± 15.9 years). The differences in total cholesterol (13.48 ± 7.4 vs. 11.02 ± 3.5 mmol/L) and LDL-C levels (10.89 ± 6.6 vs. 8.58 ± 3.26 mmol/L) between the groups were not statistically significant. Interestingly, vascular complications were more frequent in sHeFH group as well (4 vs. 1 patients). In neither the HoFH nor the sHeFH group were we able to achieve the target LDL-C levels, due in part to the specific features of the reimbursement system, patient and parental preferences, the extremely high baseline LDL-C levels, and certain genetic characteristics. Conclusions: Our findings highlight the importance of genetic testing-based personalized therapy in these specific patient subpopulations. We emphasize that serum LDL-C alone is insufficient to distinguish between HoFH and sHeFH patients, and that therapeutic challenges should be anticipated in both groups arising partly from limited patient adherence as well as from financial constraints.