Apolipoprotein C-III, familial chylomicronemia syndrome, and olezarsen.

Reducing the synthesis of apoC-III reduces fasting triglycerides in individuals lacking lipoprotein lipase activity. Recently, Stroes et al.1 published a phase 3 trial on the effects of olezarsen, a third-generation antisense oligonucleotide that blocks apoC-III mRNA, on triglycerides and risk of acute pancreatitis.

Olezarsen, Acute Pancreatitis, and Familial Chylomicronemia Syndrome.

BACKGROUND: Familial chylomicronemia syndrome is a genetic disorder associated with severe hypertriglyceridemia and severe acute pancreatitis. Olezarsen reduces the plasma triglyceride level by reducing hepatic synthesis of apolipoprotein C-III. METHODS: In a phase 3, double-blind, placebo-controlled trial, we randomly assigned patients with genetically identified familial chylomicronemia syndrome to receive olezarsen at a dose of 80 mg or 50 mg or placebo subcutaneously every 4 weeks for 49 weeks. There were two primary end points: the difference between the 80-mg olezarsen group and the placebo group in the percent change in the fasting triglyceride level from baseline to 6 months, and (to be assessed if the first was significant) the difference between the 50-mg olezarsen group and the placebo group. Secondary end points included the mean percent change from baseline in the apolipoprotein C-III level and an independently adjudicated episode of acute pancreatitis. RESULTS: A total of 66 patients underwent randomization; 22 were assigned to the 80-mg olezarsen group, 21 to the 50-mg olezarsen group, and 23 to the placebo group. At baseline, the mean (±SD) triglyceride level among the patients was 2630±1315 mg per deciliter, and 71% had a history of acute pancreatitis within the previous 10 years. Triglyceride levels at 6 months were significantly reduced with the 80-mg dose of olezarsen as compared with placebo (-43.5 percentage points; 95% confidence interval [CI], -69.1 to -17.9; P<0.001) but not with the 50-mg dose (-22.4 percentage points; 95% CI, -47.2 to 2.5; P = 0.08). The difference in the mean percent change in the apolipoprotein C-III level from baseline to 6 months in the 80-mg group as compared with the placebo group was -73.7 percentage points (95% CI, -94.6 to -52.8) and between the 50-mg group as compared with the placebo group was -65.5 percentage points (95% CI, -82.6 to -48.3). By 53 weeks, 11 episodes of acute pancreatitis had occurred in the placebo group, and 1 episode had occurred in each olezarsen group (rate ratio [pooled olezarsen groups vs. placebo], 0.12; 95% CI, 0.02 to 0.66). Adverse events of moderate severity that were considered by a trial investigator at the site to be related to the trial drug or placebo occurred in 4 patients in the 80-mg olezarsen group. CONCLUSIONS: In patients with familial chylomicronemia syndrome, olezarsen may represent a new therapy to reduce plasma triglyceride levels. (Funded by Ionis Pharmaceuticals; Balance ClinicalTrials.gov number, NCT04568434.).

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolaemia: An expert consensus statement from ERKNet and ESPN.

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is used for decades, lowering serum LDL-C levels by more than 70% directly after the treatment. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment goals and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Long-term clinical outcomes and management of hypertriglyceridemia in children with Apo-CII deficiency.

BACKGROUND AND AIM: APO CII, one of several cofactors which regulate lipoprotein lipase enzyme activity, plays an essential role in lipid metabolism. Deficiency of APO CII is an ultra-rare autosomal recessive cause of familial chylomicronemia syndrome. We present the long-term clinical outcomes of 12 children with APO CII deficiency. METHODS AND RESULTS: The data of children with genetically confirmed APO CII deficiency were evaluated retrospectively. Twelve children (8 females) with a mean follow-up of 10.1 years (±3.9) were included. At diagnosis, the median age was 60 days (13 days-10 years). Initial clinical findings included lipemic serum (41.6%), abdominal pain (41.6%), and vomiting (16.6%). At presentation, the median triglyceride (TG) value was 4341 mg/dL (range 1277-14,110). All patients were treated with a restricted fat diet, medium-chain triglyceride (MCT), and omega-3-fatty acids. In addition, seven patients (58.3%) received fibrate. Fibrate was discontinued in two patients due to rhabdomyolysis and in one patient because of cholelithiasis. Seven (58.3%) patients experienced pancreatitis during the follow-up period. One female experienced recurrent pancreatitis and was treated with fresh frozen plasma (FFP). CONCLUSIONS: Apo CII deficiency is an ultra-rare autosomal recessive condition of hypertriglyceridemia associated with significant morbidity and mortality. Low-fat diet and MCT supplementation are the mainstays of therapy, while the benefit of TG-lowering agents are less well-defined.

Acute pancreatitis risk in multifactorial chylomicronemia syndrome depends on the molecular cause of severe hypertriglyceridemia.

BACKGROUND AND AIMS: Multifactorial chylomicronemia syndrome (MCS) is a severe form of hypertriglyceridemia (hyperTG) associated with an increased risk of acute pancreatitis (AP). Severe hyperTG is mainly polygenic in nature, either caused by the presence of heterozygous pathogenic variants (PVs) in TG-related metabolism genes or by accumulation of common variants in hyperTG susceptibility genes. This study aims to determine if the risk of AP is similar amongst MCS patients with different molecular causes of severe hyperTG. METHODS: This study included 114 MCS patients who underwent genetic testing for PVs in TG-related metabolism genes and 16 single nucleotide polymorphisms (SNPs) in hyperTG susceptibility genes. A weighted TG-polygenic risk score (TG-PRS) was calculated. A TG-PRS score ≥ 90th percentile was used to define a high TG-PRS. RESULTS: Overall, 66.7% of patients had severe hyperTG of polygenic origin. MCS patients with only a PV and those with both a PV and high TG-PRS were more prone to have maximal TG concentration ≥ 40 mmol/L (OR 5.33 (1.55-18.36); p = 0.008 and OR 5.33 (1.28-22.25); p = 0.02), as well as higher prevalence of AP (OR 3.64 (0.89-14.92); p = 0.07 and OR 11.90 (2.54-55.85); p = 0.002) compared to MCS patients with high TG-PRS alone. CONCLUSIONS: This is the first study to show that MCS caused by a high TG-PRS and a PV is associated with higher risk of AP, similar to what is seen in the monogenic form of severe hyperTG. This suggests that determining the molecular cause of severe hyperTG could be useful to stratify the risk of pancreatitis in MCS.

Challenges in familial chylomicronemia syndrome diagnosis and management across Latin American countries: An expert panel discussion.

Familial chylomicronemia syndrome (FCS) is a rare genetic disorder characterized by extremely high triglyceride levels due to impaired clearance of chylomicrons from plasma. This paper is the result of a panel discussion with Latin American specialists who raised the main issues on diagnosis and management of FCS in their countries. Overall FCS is diagnosed late on the course of the disease, is characterized by heterogeneity on the occurrence of pancreatitis, and remains a long time in care of different specialists until reaching a lipidologist. Pancreatitis and secondary diabetes are frequently seen, often due to late diagnosis and inadequate care. Molecular diagnosis is unusual; however, loss of function variants on the lipoprotein lipase gene are apparently the most frequent etiology. A founder effect of the glycosylphosphatidylinositol anchored high density lipoprotein binding protein 1 gene has been described in the northeast of Brazil. Low awareness of the disease amongst health professionals contributes to inadequate care and an inadequate patient journey.

Comparison of plasmapheresis with medical apheresis in terms of efficacy and cost in the acute treatment of hypertriglyceridemia in children with lipoprotein lipase deficiency.

OBJECTIVES: We aimed to compare plasmapheresis and medical apheresis as lipid-lowering therapies in children with familial lipoprotein lipase (LPL) deficiency. METHODS: The data of 13 patients who were followed up after a diagnosis of LPL deficiency were retrospectively analyzed. Plasma triglyceride, cholesterol, amylase, and lipase values and complications were recorded before and after each patient underwent plasmapheresis or medical apheresis. RESULTS: The mean follow-up period of the patients was 99.64 ± 52.92 months in the medical apheresis group and 118 ± 16.97 months in the plasmapheresis group. While the mean triglyceride level before plasmapheresis was 1,875.38 ± 547.46 mg/dL, it was 617 ± 228.28 mg/dL after plasmapheresis. While the mean triglyceride level before medical apheresis was 1,756.86 ± 749.27 mg/dL, it was found to be 623.03 ± 51.36 mg/dL after medical apheresis. Triglyceride levels were decreased by 59.62% with medical apheresis and 65.57% with plasmapheresis. The cost of treatment for medical apheresis was found to be lower compared to plasmapheresis 296.93 ± 29.94 Turkish lira (USD 43.34 ± 4.01) vs. 3,845.42 ± 156.17 Turkish lira (USD 561.37 ± 20.93; p<0.001). CONCLUSIONS: Although there is no standardized strategy for the acute treatment of hypertriglyceridemia due to LPL deficiency, medical apheresis is a safe and effective treatment with a low risk of side effects. Unlike plasmapheresis, medical apheresis can be performed in any center, which is another important advantage of the procedure.

Current Diagnosis and Management of Primary Chylomicronemia.

Primary chylomicronemia (PCM) is a rare and intractable disease characterized by marked accumulation of chylomicrons in plasma. The levels of plasma triglycerides (TGs) typically range from 1,000 - 15,000 mg/dL or higher.PCM is caused by defects in the lipoprotein lipase (LPL) pathway due to genetic mutations, autoantibodies, or unidentified causes. The monogenic type is typically inherited as an autosomal recessive trait with loss-of-function mutations in LPL pathway genes (LPL, LMF1, GPIHBP1, APOC2, and APOA5). Secondary/environmental factors (diabetes, alcohol intake, pregnancy, etc.) often exacerbate hypertriglyceridemia (HTG). The signs, symptoms, and complications of chylomicronemia include eruptive xanthomas, lipemia retinalis, hepatosplenomegaly, and acute pancreatitis with onset as early as in infancy. Acute pancreatitis can be fatal and recurrent episodes of abdominal pain may lead to dietary fat intolerance and failure to thrive.The main goal of treatment is to prevent acute pancreatitis by reducing plasma TG levels to at least less than 500-1,000 mg/dL. However, current TG-lowering medications are generally ineffective for PCM. The only other treatment options are modulation of secondary/environmental factors. Most patients need strict dietary fat restriction, which is often difficult to maintain and likely affects their quality of life.Timely diagnosis is critical for the best prognosis with currently available management, but PCM is often misdiagnosed and undertreated. The aim of this review is firstly to summarize the pathogenesis, signs, symptoms, diagnosis, and management of PCM, and secondly to propose simple diagnostic criteria that can be readily translated into general clinical practice to improve the diagnostic rate of PCM. In fact, these criteria are currently used to define eligibility to receive social support from the Japanese government for PCM as a rare and intractable disease.Nevertheless, further research to unravel the molecular pathogenesis and develop effective therapeutic modalities is warranted. Nationwide registry research on PCM is currently ongoing in Japan with the aim of better understanding the disease burden as well as the unmet needs of this life-threatening disease with poor therapeutic options.

Apolipoprotein C-III and cardiovascular diseases: when genetics meet molecular pathologies.

Cardiovascular diseases (CVD) have overtaken infectious diseases and are currently the world's top killer. A quite strong linkage between this type of ailments and elevated plasma levels of triglycerides (TG) has been always noticed. Notably, this risk factor is mired in deep confusion, since its role in atherosclerosis is uncertain. One of the explanations that aim to decipher this persistent enigma was provided by apolipoprotein C-III (apoC-III), a small protein historically recognized as an important regulator of TG metabolism. Preeminently, hundreds of studies have been carried out in order to explore the APOC3 genetic background, as well as to establish a correlation between its variants and dyslipidemia-related disorders, pointing to an earnest predictive power for future outcomes. Among several polymorphisms reported within the APOC3, the SstI site in its 3'-untranslated region (3'-UTR) was the most consistently and robustly associated with an increased CVD risk. As more genetic data supporting its importance in cardiovascular events aggregate, it was declared, correspondingly, that apoC-III exerts various atherogenic effects, either by intervening in the function and catabolism of many lipoproteins, or by inducing endothelial inflammation and smooth muscle cells (SMC) proliferation. This review was designed to shed the light on the structural and functional aspects of the APOC3 gene, the existing association between its SstI polymorphism and CVD, and the specific molecular mechanisms that underlie apoC-III pathological implications. In addition, the translation of all these gathered knowledges into preventive and therapeutic benefits will be detailed too.

Evaluation of the chylomicron-TG to VLDL-TG ratio for type I hyperlipoproteinemia diagnostic.

BACKGROUND: The aim of this study is to confirm the diagnostic performance of the Chylomicron to very low-density lipoproteins triglycerides (CM/VLDL-TG) ratio, the triglycerides to cholesterol ratio (TG/TC) and a dichotomic rule including the tryglycerides to apolipoprotein B (TG/APOB) ratio for the presence of Type I hyperlipoproteinemia (HPLI) in patients with severe hypertriglyceridemia (sHTG) that were at high risk for familial chylomicronemia syndrome (FCS). METHODS: Two cohorts (derivation and validation) of patients with sHTG were included in the study. Anthropometric, clinical, biochemical and genetic data were obtained. The CM/VLDL-TG, TG/TC and TG/APOB ratios were calculated. Finally, a diagnostic performance study was developed to establish sensitivity, specificity and cut-offs by a ROC curve analysis in the derivation cohort as well as agreement and predictive values in the validation cohort. RESULTS: Patients with FCS in both cohorts showed an earlier presence in pancreatitis, greater number of acute pancreatitis episodes and lower BMI. FCS patients also showed higher ratios of CM/VLDL-TG, TG/TC and TG/APOB ratios, whereas their HDL-C, LDL-C and APOB levels were lower than in non-FCS patients. Sensitivity and agreement were low for both the TG/TC and TG/APOB ratios, although predictive values were good. The CM/VLDL-TG ratio showed greatest sensitivity, specificity, agreement and predictive values for cut-off of 3.8 and 4.5. CONCLUSIONS: Our results suggest that in subjects at high risk of FCS a total serum TG/TC ratio or TG/APOB ratio are feasible to initially screen for HLPI; however, a CM/VLDL-TG ratio ≥4.5 is a better diagnostic criterion for HPLI.

Chylomicronemia syndrome: Familial or not?

BACKGROUND: Chylomicronemia syndrome (CS) is a metabolic condition characterized by severely elevated plasma triglycerides (>880 mg/dL) and high rates of morbidity and mortality. The syndrome can be classified into two major groups: monogenic familial chylomicronemia syndrome (FCS) and multifactorial chylomicronemia syndrome (MCS), the frequencies of which are ill-defined. OBJECTIVE: The objective of the study was to characterize the prevalence of the most common and rarest subsets of this syndrome, MCS and FCS, respectively, in a single-center, real-world setting. METHODS: This was a retrospective cross-sectional study of patients with plasma triglycerides ≥880 mg/dL. The criteria used for identification of patients with FCS were modeled after a Food and Drug Administration endorsed set of parameters. Less stringent criteria that removed the requirement for pancreatitis were used to classify MCS. Full criteria are described in detail in the article. RESULTS: Of the 2,342,136 patient records queried, 578 had triglycerides ≥880 mg/dL (0.025%), of which 86 had a documented history of pancreatitis. Five patients who met the criteria for FCS were identified (three genetically confirmed), resulting in an estimated prevalence of ~1-2 per 1,000,000. On the other hand, MCS was identified in 186 patients, corresponding to an estimated prevalence of ~1 in 12,000. There were 5181 cases of pancreatitis (0.22% of the entire cohort), 86 of which occurred in subjects with triglycerides≥880 mg/dL (1.7% of cases of pancreatitis). Rates of pancreatitis in this subset were elevated at 6.5%, 100%, and 17.8%, among patients with MCS, FCS, and secondary hypertriglyceridemia, respectively. CONCLUSIONS: CS is an uncommon condition, but it is associated with significant complications, regardless of etiology. Among patients with CS, MCS was 40- to 60-fold more prevalent than FCS and associated with frequent morbidity. Therefore, disease recognition and treatment should extend to all forms of CS pursuant to the clinical presentation.

Familial chylomicronemia syndrome: A rare but devastating autosomal recessive disorder characterized by refractory hypertriglyceridemia and recurrent pancreatitis.

Familial Chylomicronemia Syndrome (FCS) is a rare autosomal recessive lipid disorder characterized by severe hypertriglyceridemia and recurrent pancreatitis. Because the disorder is often misdiagnosed or not diagnosed and because traditional triglyceride lowering medications are often ineffective, the disease leads to a tremendous physical, social and emotional burden on afflicted patients and their caretakers. Mutations in 5 different genes have been implicated in the development of FCS, all of which have an effect on the activity of lipoprotein lipase. Lipoprotein lipase(LPL) is responsible for removing triglycerides from chylomicrons and other triglyceride rich lipoproteins in the circulation, breaking them down into free fatty acids for use as energy. Patients with FCS have loss of function of their LPL leading to severely elevated chylomicrons in the circulation and hence, severe hypertriglyceridemia. The principle treatment for FCS is to reduce chylomicron formation in the gut by placing the patient on an extremely low fat diet. New medications in development hold significant promise for improving the quality of life for FCS patients.

Volanesorsen and Triglyceride Levels in Familial Chylomicronemia Syndrome.

BACKGROUND: Familial chylomicronemia syndrome is a rare genetic disorder that is caused by loss of lipoprotein lipase activity and characterized by chylomicronemia and recurrent episodes of pancreatitis. There are no effective therapies. In an open-label study of three patients with this syndrome, antisense-mediated inhibition of hepatic APOC3 mRNA with volanesorsen led to decreased plasma apolipoprotein C-III and triglyceride levels. METHODS: We conducted a phase 3, double-blind, randomized 52-week trial to evaluate the safety and effectiveness of volanesorsen in 66 patients with familial chylomicronemia syndrome. Patients were randomly assigned, in a 1:1 ratio, to receive volanesorsen or placebo. The primary end point was the percentage change in fasting triglyceride levels from baseline to 3 months. RESULTS: Patients receiving volanesorsen had a decrease in mean plasma apolipoprotein C-III levels from baseline of 25.7 mg per deciliter, corresponding to an 84% decrease at 3 months, whereas patients receiving placebo had an increase in mean plasma apolipoprotein C-III levels from baseline of 1.9 mg per deciliter, corresponding to a 6.1% increase (P<0.001). Patients receiving volanesorsen had a 77% decrease in mean triglyceride levels, corresponding to a mean decrease of 1712 mg per deciliter (19.3 mmol per liter) (95% confidence interval [CI], 1330 to 2094 mg per deciliter [15.0 to 23.6 mmol per liter]), whereas patients receiving placebo had an 18% increase in mean triglyceride levels, corresponding to an increase of 92.0 mg per deciliter (1.0 mmol per liter) (95% CI, -301.0 to 486 mg per deciliter [-3.4 to 5.5 mmol per liter]) (P<0.001). At 3 months, 77% of the patients in the volanesorsen group, as compared with 10% of patients in the placebo group, had triglyceride levels of less than 750 mg per deciliter (8.5 mmol per liter). A total of 20 of 33 patients who received volanesorsen had injection-site reactions, whereas none of the patients who received placebo had such reactions. No patients in the placebo group had platelet counts below 100,000 per microliter, whereas 15 of 33 patients in the volanesorsen group had such levels, including 2 who had levels below 25,000 per microliter. No patient had platelet counts below 50,000 per microliter after enhanced platelet-monitoring began. CONCLUSIONS: Volanesorsen lowered triglyceride levels to less than 750 mg per deciliter in 77% of patients with familial chylomicronemia syndrome. Thrombocytopenia and injection-site reactions were common adverse events. (Funded by Ionis Pharmaceuticals and Akcea Therapeutics; APPROACH Clinical Trials.gov number, NCT02211209.).

Metabolism and Disposition of Volanesorsen, a 2'-O-(2 methoxyethyl) Antisense Oligonucleotide, Across Species.

Volanesorsen (previously known as ISIS 304801) is a 20-nucleotide partially 2'-O-(2-methoxyethyl) (2'-MOE)-modified antisense oligonucleotide (ASO) gapmer, which was recently approved in the European Union as a novel, first-in-class treatment in the reduction of triglyceride levels in patients with familial chylomicronemia syndrome. We characterized the absorption, distribution, metabolism, and excretion characteristics of volanesorsen in mice, rats, monkeys, and humans, in either radiolabeled or nonradiolabeled studies. This also included the characterization of all of the observed ASO metabolite species excreted in urine. Volanesorsen is highly bound to plasma proteins that are similar in mice, monkeys, and humans. In all species, plasma concentrations declined in a multiphasic fashion, characterized by a relatively fast initial distribution phase and then a much slower terminal elimination phase following subcutaneous bolus administration. The plasma metabolite profiles of volanesorsen are similar across species, with volanesorsen as the major component. Various shortened oligonucleotide metabolites (5-19 nucleotides long) were identified in tissues in the multiple-dose mouse and monkey studies, but fewer in the [3H]-volanesorsen rat study, likely due to a lower accumulation of metabolites following a single dose in rats. In urine, all metabolites identified in tissues were observed, consistent with both endo- and exonuclease-mediated metabolism and urinary excretion being the major elimination pathway for volanesorsen and its metabolites. SIGNIFICANCE STATEMENT: We characterized the absorption, distribution, metabolism, and excretion (ADME) of volanesorsen, a partially 2'-MOE-modified antisense oligonucleotide, from mouse to man utilizing novel extraction and quantitation techniques in samples collected from preclinical toxicology studies, a 3H rat ADME study, and a phase 1 clinical trial.

Deciphering the role of V200A and N291S mutations leading to LPL deficiency.

BACKGROUND AND AIMS: Type I hyperlipoproteinemia is an autosomal recessive disorder of lipoprotein metabolism caused by mutations in the LPL gene, with an estimated prevalence in the general population of 1 in a million. In this work, we studied the molecular mechanism of two known mutations in the LPL gene in ex vivo and in vitro experiments and also the effect of two splice site mutations in ex vivo experiments. METHODS: Two patients with hypertriglyceridemia were selected from the Lipid Clinic in Vienna. The first patient was compound heterozygote for c.680T > C (exon 5; p.V200A) and c.1139+1G > A (intron 7 splice site). The second patient was compound heterozygote for c.953A > G (exon 6; p.N291S) and c.1019-3C > A (intron 6 splice site). The LPL gene was sequenced and post-heparin plasma samples (ex vivo) were used to test LPL activity. In vitro experiments were performed in HEK 293T/17 cells transiently transfected with wild type or mutant LPL plasmids. Cell lysate and media were used to evaluate LPL production, secretion, activity and dimerization by Western blot analysis and LPL enzymatic assay, respectively. RESULTS: Our data show that in both patients, LPL activity is absent. V200A is a mutation that alters LPL secretion and activity whereas the N291S mutation affects LPL activity, but both mutations do not affect dimerization. The effect of these mutations in patients is more severe since they have splice site mutations on the other allele. CONCLUSIONS: We characterized these LPL mutations at the molecular level showing that are pathogenic.

Chylomicronemia: Differences between familial chylomicronemia syndrome and multifactorial chylomicronemia.

BACKGROUND AND AIMS: Chylomicronemia can be either monogenic or multifactorial. The monogenic form, namely familial chylomicronemia syndrome (FCS), is a rare autosomal recessive disease that strongly predisposes to pancreatitis. However, the clinical variables differentiating FCS from multifactorial chylomicronemia (MCM) are not well established. The aims of the present study were to describe a well-defined cohort of FCS subjects and to investigate the differences between patients with FCS and MCM. METHODS: A total of 25 FCS and 36 MCM patients were included in the present study. FCS patients were genetically confirmed, whereas MCM patients had negative genetic testing, triglycerides above 10 mmol/L at least once and the presence of both chylomicrons and VLDL in plasma. RESULTS: FCS patients presented a significant higher frequency of pancreatitis (60% vs. 6%), multiple pancreatitis (48% vs. 3%) and abdominal pain (63% vs. 19%) and a lower frequency of metabolic abnormalities than in the MCM group (p < 0.0001). In addition, the frequency of cardiovascular events was higher in the MCM group than in the FCS group (17% vs. 0%), although the difference was not statistically significant (p = 0.07). In a univariate regression model, the significant predictors of FCS were age at first manifestation (ß = -2.11, p = 0.0005), body mass index (BMI) (ß = -1.82, p < 0.001) and gamma-glutamyl transferase (GGT) (ß = -1.64, p = 0.001). CONCLUSIONS: Our study identified several variables that significantly differentiates FCS from MCM patients. These results need to be replicated in larger cohorts to identify the independent predictors of FCS.

Identification and diagnosis of patients with familial chylomicronaemia syndrome (FCS): Expert panel recommendations and proposal of an "FCS score".

Familial chylomicronaemia syndrome (FCS) is a rare, inherited disorder characterised by impaired clearance of triglyceride (TG)-rich lipoproteins from plasma, leading to severe hypertriglyceridaemia (HTG) and a markedly increased risk of acute pancreatitis. It is due to the lack of lipoprotein lipase (LPL) function, resulting from recessive loss of function mutations in the genes coding LPL or its modulators. A large overlap in the phenotype between FCS and multifactorial chylomicronaemia syndrome (MCS) contributes to the inconsistency in how patients are diagnosed and managed worldwide, whereas the incidence of acute hypertriglyceridaemic pancreatitis is more frequent in FCS. A panel of European experts provided guidance on the diagnostic strategy surrounding FCS and proposed an algorithm-based diagnosis tool for identification of these patients, which can be readily translated into practice. Features included in this FCS score comprise: severe elevation of plasma TGs (fasting TG levels >10 mmol/L [885 mg/dL] on multiple occasions), refractory to standard TG-lowering therapies, a young age at onset, the lack of secondary factors (except for pregnancy and oral oestrogens) and a history of episodes of acute pancreatitis. Considering 53 FCS patients from three cohorts and 52 MCS patients from three cohorts, the overall sensitivity of the FCS score (≥10) was 88% (95% confidence interval [CI]: 0.76, 0.97) with an overall specificity of 85% (95% CI: 0.75, 0.94). Receiver operating characteristic curve area was 0.91. Pragmatic clinical scoring, by standardising diagnosis, may help differentiate FCS from MCS, may alleviate the need for systematic genotyping in patients with severe HTG and may help identify high-priority candidates for genotyping.

Orlistat Therapy for Children With Type 1 Hyperlipoproteinemia: A Randomized Clinical Trial.

Context: Patients with type 1 hyperlipoproteinemia (T1HLP), a rare genetic disorder, have extreme chylomicronemia and recurrent episodes of acute pancreatitis. Currently, the only therapeutic option is to consume an extremely low-fat diet because the triglyceride-lowering medications are not efficacious. Objective: To determine the efficacy of orlistat, a gastric and pancreatic lipase inhibitor, in reducing serum triglyceride levels in patients with T1HLP. Design and Setting: We conducted a randomized, open-label, clinical trial with a four-period, two-sequence ("orlistat" and "off orlistat" for 3 months), crossover study design. Patients: Two unrelated young Asian Indian males (11 and 9 years old) with T1HLP due to homozygous large GPIHBP1 deletions were enrolled at the UT Southwestern Medical Center. The patients were randomized to receive 3 months of orlistat or no therapy (off), then crossed over to the other arm, and this sequence was then repeated. Fasting serum triglyceride levels, fat-soluble vitamins, and gastrointestinal side effects were assessed. Results: Compared with the two off periods, orlistat therapy reduced serum triglycerides by 53.3% and 53.0% in patient 1 and 45.8% and 62.2% in patient 2. There was no deficiency of fat-soluble vitamin levels, and their growth continued. There were no serious adverse effects of orlistat; patient 1 had a mild increase in passage of gas and bloating, and patient 2 had constipation with mild stool leakage. Conclusion: Orlistat is safe and highly efficacious in lowering serum triglycerides in children with T1HLP and should be the first-line therapy in conjunction with an extremely low-fat diet.