Background: Determinants of coronary artery calcification (CAC) prevalence and severity in heterozygous familial hypercholesterolemia (HeFH) remain understudied. The objective of this cross-sectional study was to investigate correlates of CAC in patients with HeFH. Methods: A CAC score was calculated by a noncontrast computed tomography scan in women (n ¼ 68) and men (n ¼ 78) with genetically defined HeFH. We classified CAC prevalence and severity using 3 categories: CAC score ¼ 0 Agatston Unit (AU), CAC score ¼ 1-100 AU, and CAC score > 100 AU. Information on potential correlates of CAC including familial and personal health history, cardiovascular risk factors, lipid-lowering medication, and lifestyle habits was collected. R ESUM E Contexte : Les d eterminants de la pr evalence et de la s ev erit e de la calcification des artères coronaires (CAC) dans l'hypercholest erol emie familiale h et erozygote (HFHe) demeurent peu etudi es. L'objectif de cette etude transversale etait d'identifier les corr elats de la CAC chez des patients atteints d'HFHe. M ethodologie : Un score calcique coronarien (SCC) a et e calcul e par un examen de tomodensitom etrie sans contraste chez des femmes (n ¼ 68) et des hommes (n ¼ 78) avec HFHe g en etiquement d efinie. Nous avons class e la pr evalence et la gravit e de la CAC en trois cat egories : SCC ¼ 0 unit e d'Agatston (UA), SCC ¼ 1 à 100 UA et SCC > 100 UA. Des renseignements ont et e recueillis sur des corr elats Heterozygous (He) familial hypercholesterolemia (FH) is an inherited, autosomal dominant disease caused by genetic mutations in the low-density lipoprotein (LDL) receptor (LDLR), apolipoprotein B (apo B), or proprotein convertase subtilisin/kexin type 9. 1 By disrupting the normal clearance of LDLs from the plasma, these mutations cause a marked hypercholesterolemia across the lifespan. HeFH's main clinical feature is a 2-to 3-fold increase in plasma LDL-cholesterol (LDL-C) concentrations, typically ranging from 5.0 to 14.0 mmol/L. If untreated, individuals with HeFH face a 10-to 20-fold increased risk of coronary heart disease (CHD) compared with unaffected individuals, and CHD usually occurs prematurely before the age of 55 years. HeFH is estimated to affect 1 in 310 individuals according to most recent estimates. 2,3 Worldwide, HeFH is the most prevalent genetic disorder, causing premature coronary events and deaths. 1Although individuals with HeFH undisputedly face a lifelong increased risk of CHD compared with non-affected individuals, 4 they also present highly heterogeneous CHD risk profiles. 5 Age, male sex, body mass index (BMI), smoking status, blood pressure, and concentrations of LDL-C, HDL-C, and lipoprotein(a) (Lp(a)) are all associated with the prevalence and incidence of CHD in HeFH. 6,7 However, prevalence and CJC Open 3 (2021) 62e70