Preliminary Findings of the EPIRUS Familial Hypercholesterolemia Reverse Cascade Program for Pediatric Targeted Screening

Background: Familial hypercholesterolemia (FH) causes lifelong elevation of low-density lipoprotein cholesterol (LDL-C) and increases the risk of premature cardiovascular disease (CVD). Despite effective therapies, FH remains substantially underdiagnosed worldwide. Objective: To evaluate the diagnostic yield and clinical characteristics of targeted pediatric FH screening within the EPIRUS FH reverse cascade project. Materials and Methods: This observational cohort study evaluated children aged 4–16 years in a regional screening program in Northwestern Greece. Eligibility included LDL-C ≥160 mg/dL, LDL-C ≥130 mg/dL with a family history of hyperlipidemia or premature CVD, or lipid-lowering therapy use for suspected FH. Biochemical evaluation and next-generation sequencing (LDL receptor [ LDLR ], apolipoprotein B [ ApoB ], and proprotein convertase subtilisin/kexin type 9 [ PCSK9 ]) were performed to determine genetic diagnostic yield, pathogenic variant distribution, and clinical associations with genetic positivity. Results: Among 230 participants (mean age 9.37 years), 60% had genetically confirmed FH, 37% tested negative, and 3% had variants of uncertain significance. Three participants were homozygous for FH. Pathogenic variants primarily occurred in LDLR (92%), followed by ApoB (6%) and PCSK9 ( 2%). Genetically positive children exhibited significantly higher LDL-C (mean difference + 56.16 mg/dL, P = 0.001) and total cholesterol (+48.50 mg/dL, P = 0.003), and more frequently reported a family history of premature CVD (61.5% vs. 40.3%, P = 0.005). Conclusions: Targeted pediatric screening combined with genetic testing achieves a high diagnostic yield in clinically selected pediatric populations. The EPIRUS FH project demonstrates the feasibility of integrating pediatric testing into routine clinical practice for early detection and family-based reverse cascade screening.