Familial chylomicronemia syndrome (FCS) is an ultra-rare phenotype that is usually caused by biallelic mutations in the LPL gene encoding lipoprotein lipase, or less often in APOC2, APOA5, LMF1, or GPIHBP1 genes encoding cofactors or interacting proteins. We evaluated baseline phenotypes among FCS participants in a phase 3 randomized placebo-controlled trial of volanesorsen (NCT02211209). Baseline clinical, fasting, and postfat load metabolic markers were assessed. Targeted next-generation DNA sequencing plus custom bioinformatics was used to genotype subjects. Among 52 FCS individuals, 41 had biallelic LPL gene mutations (LPL-FCS patients): 82%, 7%, and 11% were missense, nonsense, and splicing variants, respectively. Eleven individuals had non-LPL-FCS; 2 had mutations in APOA5, 5 in GPIHBP1, and 1 each in LMF1 and APOC2 genes, respectively. Two other individuals were double heterozygotes, each with 1 normal LPL allele. All subjects had extremely high triglycerides (TGs) and chylomicrons, but very low levels of other lipoproteins. Compared with LPL-FCS individuals, non-LPL-FCS individuals were very similar for most traits, but had significantly higher postheparin LPL activity, higher 4-hour postprandial insulin and C-peptide levels; and higher low-density lipoprotein cholesterol levels. In non-LPL-FCS individuals compared to those with LPL-FCS, there were also nonsignificant trends toward lower levels of total and chylomicron TGs, lower 4-hour postprandial chylomicron TG levels, and higher very-low-density lipoprotein TG levels. Thus, LPL FCS and non-LPL FCS are largely phenotypically similar. However, LPL FCS patients have lower postheparin LPL activity and a trend toward higher TGs, whereas low-density lipoprotein cholesterol was higher in non-LPL-FCS patients.

In contrast to strong evidence-based clinical recommendations for lipid-lowering treatment, there is no analogous definitive diagnostic definition of hypercholesterolemia and its various subtypes. For many clinicians, guideline indications for hypolipidemic treatment can become broadly conflated with hypercholesterolemia in a non-specific sense. In this statement, we propose a unified definition and mechanism-based classification of hypercholesterolemia, which in turn should help to stratify patients and guide efficient diagnosis without interfering with the current strategies of ASCVD risk reduction.

Objective— To investigate the significance of tendon xanthomas (TX) in heterozygous subjects with familial hypercholesterolemia (hFH). Methods and Results— 951 men and women with genetic diagnosis of hFH were studied, of whom 278 (29.2%) presented TX. TX frequency increased with age from 6.9% in subjects 20 to 30 years to 38.3% at 51 to 60 years, with a decrease in those older than 60 years. Total and low-density lipoprotein (LDL) cholesterol were higher in TX ⁺ than in TX ⁻ subjects (439.0±78.5 mg/dL and 363.1±76.5 mg/dL versus 400.6±73.4 and 323.3±71.0, respectively; P =0.001). High-density lipoprotein (HDL) cholesterol was lower in TX ⁺ than in TX ⁻ subjects (50.4±15.0 mg/dL versus 53.1±14.8 mg/dL; P =0.005). Lp(a), apolipoprotein E genotype, and type of LDL receptor gene mutation showed no differences between groups. 102 TX ⁺ reported premature cardiovascular disease (CVD) (36.7%) versus 93 TX ⁻ (13.8%) ( P =0.001). The relative odds for premature CVD were higher in women (4.49 versus 2.26), and increased in hFH younger than 51 years to 3.60 (95% CI, 1.703 to 7.608) in men and to 17.1 (95% CI, 2.697 to 108.920) in women. In the multivariate analysis, age, male sex, LDL cholesterol, and hypertension showed significant positive association with TX, whereas body mass index showed negative association with TX. Conclusions— TX are associated with cardiovascular risk factors and higher CVD, indicating that their detection indicates the need for more aggressive lipid-lowering intervention.

Background: Spain, a Mediterranean country with relatively low rates of coronary heart disease, has a high prevalence of traditional cardiovascular risk factors and is experiencing a severe epidemic of overweight/obesity. We designed the Aragon Workers’ Health Study (AWHS) to characterize the factors associated with metabolic abnormalities and subclinical atherosclerosis in a middle aged population in Spain free of clinical cardiovascular disease. The objective of this paper is to describe the study design, aims and baseline characteristics of participants in the AWHS. Methods/Design: Longitudinal cohort study based on the annual health exams of 5,400 workers of a car assembly plant in Figueruelas (Zaragoza, Spain). Study participants were recruited during a standardized clinical exam in 2009–2010 (participation rate 95.6%). Study participants will undergo annual clinical exams and laboratory assays, and baseline and triennial collection of biological materials for biobanking and cardiovascular imaging exams (carotid, femoral and abdominal ultrasonography, coronary calcium score, and ankle-arm blood pressure index). Participants will be followed-up for 10 years. Results: The average (SD) age, body mass index, and waist circumference were 49.3 (8.7) years, 27.7 (3.6) kg/m² and 97.2 (9.9) cm, respectively, among males (N = 5,048), and 40.8 (11.6) years, 24.4 (3.8) kg/m², and 81.9 (9.9) cm, among females (N = 351). The prevalence of overweight, obesity, current smoking, hypertension, hypercholesterolemia, and diabetes were 55.0, 23.1, 37.1, 40.3, 75.0, and 7.4%, respectively, among males, and 23.7, 8.3, 45.0, 12.1, 59.5, and 0.6%, respectively, among females. In the initial 587 study participants who completed all imaging exams (94.5% male), the prevalence of carotid plaque, femoral plaque, coronary calcium score >1 to 100, and coronary calcium score >100 was 30.3, 56.9, 27.0, and 8.8%, respectively. 67.7% of study participants had at least one plaque in the carotid or femoral arteries. Discussion: Baseline data from the AWHS show a high prevalence of cardiovascular risk factors and of sublinical atherosclerosis. Follow-up of this cohort will allow the assessment of subclinical atherosclerosis progression and the link of disease progression to traditional and emergent risk factors.