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Introduction: Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive condition. Effective treatment is important as patients are at risk for severe and potentially fatal acute pancreatitis. We review recent developments in pharmacologic treatment for FCS, namely biological inhibitors of apolipoprotein (apo) C-III and angiopoietin-like protein 3 (ANGPTL3)., Areas Covered: FCS follows a biallelic inheritance pattern in which an individual inherits two pathogenic loss-of-function alleles of one of the five causal genes - LPL (in 60-80% of patients), GPIHBP1 , APOA5 , APOC2 , and LMF1 - leading to the absence of lipolytic activity. Patients present from childhood with severely elevated triglyceride (TG) levels >10 mmol/L. Most patients with severe hypertriglyceridemia do not have FCS. A strict low-fat diet is the current first-line treatment, and existing lipid-lowering therapies are minimally effective in FCS. Apo C-III inhibitors are emerging TG-lowering therapies shown to be efficacious and safe in clinical trials. ANGPTL3 inhibitors, another class of emerging TG-lowering therapies, have been found to require at least partial lipoprotein lipase activity to lower plasma TG in clinical trials. ANGPTL3 inhibitors reduce plasma TG in patients with multifactorial chylomicronemia but not in patients with FCS who completely lack lipoprotein lipase activity., Expert Opinion: Apo C-III inhibitors currently in development are promising treatments for FCS.

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., Competing Interests: Declaration of competing interest The authors state no conflict of interest., (Copyright © 2024 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

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., Competing Interests: Declaration of competing interest SDdF received grants from the National Institutes of Health/National Heart, Lung, and Blood Institute of the National Institutes of Health, the Family Heart Foundation and holds a patent for UpToDate, with royalties paid. AG received grants and personal fees from Amgen, Sanofi and Regeneron, Mylan Viatris, MSD, Akcea Therapeutics, Amryt, Servier, Novartis and Ultragenyx. SGP received study funding from Amgen. JH received a research grant from the National Heart, Lung, And Blood Institute of the National Institutes of Health under Award Number K23HL145109. DI received advisory honoraria from Amryt, and honoraria for lectures from Sanofi, Sobi and Novartis. CPS received advisory honoraria from Baxter, Iperboreal and Stadapharma, lecturing honoraria from Fresenius and research funding from Baxter. MK received honoraria from Abbott, Abdi Ibrahim, Amryt, LIB Therapeutics, NovoNordisk, and TR-pharma; research funding from Amryt Pharma, and participated in clinical trials with Amgen, Ionis, LIB Therapeutics, Novo Nordisk, Sanofi. RK, as head of the Apheresis Research GmbH, Cologne, Germany received financial grants for scientific research projects, honoraria for consulting and presentation of lectures including travel expenses from the companies Diamed, Cologne, Germany, and Asahi Kasei Medical, Tokyo, Japan. GK has given talks, attended conferences, received consultancy fees and participated in trials sponsored by Amgen, Novartis, Sanofi, Servier, Amryt. AW received research grants from Amgen, Regeneron, Novartis, Silence Therapeutics, Esperion, and Ultragenyx and advisory honoraria from Amryt, and Novartis. KA, EJD, LMdB, JWG, LCH, GDK, JO, RNP, MDR, CS and CT have nothing to declare., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Lipoprotein lipase (LPL) deficiency, the most common familial chylomicronemia syndrome (FCS), is a rare autosomal recessive disease characterized by chylomicronemia and severe hypertriglyceridemia (HTG), with limited clinical and genetic characterization., Objective: To describe the manifestations and management of 19 pediatric patients with LPL-FCS., Methods: LPL-FCS patients from 2014 to 2022 were divided into low-fat (LF), very-low-fat (VLF) and medium-chain-triglyceride (MCT) groups. Their clinical data were evaluated to investigate the effect of different diets. The genotype-phenotype relationship was assessed. Linear regression comparing long-chain triglyceride (LCT) intake and TG levels was analyzed., Results: Nine novel LPL variants were identified in 19 LPL-FCS pediatric patients. At baseline, eruptive xanthomas occurred in 3/19 patients, acute pancreatitis in 2/19, splenomegaly in 6/19 and hepatomegaly in 3/19. The median triglyceride (TG) level (30.3 mmol/L) was markedly increased. The MCT group and VLF group with LCT intakes <20 en% (energy percentage) had considerably lower TG levels than the LF group (both p<0.05). The LF group presented with severe HTG and significantly decreased TG levels after restricting LCT intakes to <20 en% (p<0.05). Six infants decreased TG levels to <10 mmol/L by keeping LCT intake <10 en%. TG levels and LCT intake were positively correlated in both patients under 2 years (r=0.84) and those aged 2-9 years (r=0.89). No genotype-phenotype relationship was observed., Conclusions: This study broadens the clinical and genetic spectra of LPL-FCS. The primary therapy for LPL-FCS pediatric patients is restricting dietary LCTs to <10 en% or <20 en% depending on different ages. MCTs potentially provide extra energy., (Copyright © 2023. Published by Elsevier Inc.)

A one-year-and-nine-month-old Japanese boy was admitted with hypertriglyceridemia (fasting triglycerides 2548 mg/dL). After close examination, he was diagnosed with lipoprotein lipase (LPL) deficiency (compound heterozygous) and was immediately started on a fat-restricted dietary therapy. He responded well to the regimen (1200 kcal/day, 20 g fat/day) and his triglycerides decreased to 628 mg/dL within 7 days of starting the dietary therapy. It was decided to manage his illness without using any drugs because he was still an infant and responded well to a fat-restricted diet. During his hospital stay, dietitians provided him with nutritional counseling using a food exchange list, which was designed to easily calculate the fat content by including foods that are commonly served. His family quickly learned the skills to prepare a fat-restricted diet. Moreover, since dietary restrictions may have impaired the child's growth and development, the dietitians continued to intervene regularly after the child was discharged from the hospital. The dietitians confirmed that the patient was receiving nutritional intake appropriate for his growth and discussed the dietary concerns in his daily life and how to participate in school events that involved eating and drinking. Nutritional counseling was provided every 3-4 months from disease onset to age 23 years, except for a 14-month break at age 20 years. The patient grew up without developing acute pancreatitis, a serious complication of LPL deficiency. The long-term intervention of dieticians is necessary to achieve a balance between living on a strict diet for disease management and ensuring appropriate nutritional intakes for growth/development.

Lipoprotein lipase deficiency (LPLD) results from mutations within the lipoprotein lipase (LPL) gene that lead to a complete lack of catalytically active LPL protein. Glybera was one of the first adeno-associated virus (AAV) gene replacement therapy to receive European Medicines Agency regulatory approval for the treatment of LPLD. However, Glybera is no longer marketed potentially due to a combination of economical, manufacturing, and vector-related issues. The aim of this study was to develop a more efficacious AAV gene therapy vector for LPLD. Following preclinical biodistribution, efficacy and non-Good Laboratory Practice toxicity studies with novel AAV1 and AAV8-based vectors in mice, we identified AAV8 pVR59. AAV8 pVR59 delivered a codon-optimized, human gain-of-function hLPL S447X transgene driven by a CAG promoter in an AAV8 capsid. AAV8 pVR59 was significantly more efficacious, at 10- to 100-fold lower doses, compared with an AAV1 vector based on Glybera, when delivered intramuscularly or intravenously, respectively, in mice with LPLD. Efficient gene transfer was observed within the injected skeletal muscle and liver following delivery of AAV8 pVR59, with long-term correction of LPLD phenotypes, including normalization of plasma triglycerides and lipid tolerance, for up to 6 months post-treatment. While intramuscular delivery of AAV8 pVR59 was well tolerated, intravenous administration augmented liver pathology. These results highlight the feasibility of developing a superior AAV vector for the treatment of LPLD and provide critical insight for initiating studies in larger animal models. The identification of an AAV gene therapy vector that is more efficacious at lower doses, when paired with recent advances in production and manufacturing technologies, will ultimately translate to increased safety and accessibility for patients.

Triglycerides (TGs) form part of the standard lipid profile. Elevations in TGs are associated with increased cardiovascular disease risk through triglyceride-rich lipoprotein particles found as part of non-HDL cholesterol. Many elevations of TGs are secondary to other causes, but primary hypertriglyceridaemia syndromes need to be identified. The genetic causes of hypertriglyceridaemia range from familial combined hyperlipidaemia through the autosomal recessive remnant hyperlipidaemia (related to apolipoprotein E variants) and familial chylomicronaemia syndromes. Patients with primary hypertriglyceridaemia >10 mmol/L require characterisation and specific intervention. Simple lipid profiles do not provide adequate information for detailed diagnosis and additional assays such as apolipoprotein (apo)B 100 , apoE genotype and next-generation sequencing may be useful. Management of raised TGs includes optimising diet, reducing exacerbating factors as well as lipid-lowering medications such as statins, fibrates, niacin and omega-3 fatty acids. Novel medications for orphan disease indications such as familial chylomicronaemia syndrome include volanesorsen, evinacumab and other antisense therapeutics. Extreme hypertriglyceridaemia syndromes, especially chylomicronaemia syndromes, which can be exposed by pregnancy or other factors are a medical emergency and require admission and specialist management sometimes including plasma exchange., Competing Interests: Competing interests: ASW is a site clinical investigator for clinical trials of drugs in management of familial chylomicronaemia syndrome and high triglycerides including Akcea (volanesorsen; apoC3LRx), Arrowhead (Aro-apoC3) and Regeneron (evinacumab)., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Familial chylomicronemia syndrome (FCS) is a rare genetic disease. FCS usually manifests by the age of 10 years, and 25% of cases of FCS occur during infancy. Here we present a case of FCS in a male infant and summarize our experiences on the diagnosis and therapy of this case., Patient Concerns: A male infant aged 1 month and 8 days had recurrent hematochezia and hyperchylomicronemia., Diagnosis: FCS based on symptoms and genetic test., Interventions: Plasma exchange therapy., Outcomes: His development was normal with a good spirit and satisfactory weight gain, and no hematochezia occurred again., Conclusion: Genetic test is important for accurate diagnosis of FCS, and we identified a new mutation of lipoprotein lipase gene c.88C>A which conformed to autosomal recessive inheritance. Plasma exchange therapy can be applied to infants with FCS with low risk and good outcomes., Competing Interests: All authors declare no conflicts of interest., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Context: Familial Chylomicronemia Syndrome (FCS) is an inherited disease where lack of lipoprotein lipase results in severe hypertriglyceridemia that frequently leads to recurrent acute pancreatitis. Pregnancy in patients with familial chylomicronemia syndrome (FCS) post a risk for mother and baby with potential complications (pancreatitis, miscarriage and death). Therapeutic approach includes strict dietary measures and plasma exchange. Despite the development of new drugs for FCS, their safety in pregnancy has not yet been confirmed., Case Description: We present a case of a young, pregnant female with FCS who had miscarriage in the past during one episode of acute pancreatitis. Due to the inability to achieve lower TG levels with current therapy, from 27-th week of pregnancy we have started prophylactic therapeutic plasma exchange (two times per week). Patient was followed up until the delivery of a healthy baby boy and did not experience an episode of acute pancreatitis., Conclusions: With adequate supervision and monitoring therapeutic plasma exchange represents a safe approach in pregnant women with FCS in order to reduce TGs and prevent pancreatitis. Therefore, we prevented potential complications for both mother and child., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The prevalence of hypertriglyceridemia has been increasing worldwide. Attention is drawn to the fact that the frequency of a special hypertriglyceridemia entity, named chylomicronemia syndrome, is variable among its different forms. The monogenic form, termed familial chylomicronemia syndrome, is rare, occuring in 1 in every 1 million persons. On the other hand, the prevalence of the polygenic form of chylomicronemia syndrome is around 1:600. On the basis of the genetical alterations, other factors, such as obesity, alcohol consumption, uncontrolled diabetes mellitus and certain drugs may significantly contribute to the development of the multifactorial form. In this review, we aimed to highlight the recent findings about the clinical and laboratory features, differential diagnosis, as well as the epidemiology of the monogenic and polygenic forms of chylomicronemias. Regarding the therapy, differentiation between the two types of the chylomicronemia syndrome is essential, as well. Thus, proper treatment options of chylomicronemia and hypertriglyceridemia will be also summarized, emphasizing the newest therapeutic approaches, as novel agents may offer solution for the effective treatment of these conditions., (© 2022. The Author(s).)

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.

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., (Copyright © 2021 National Lipid Association. Published by Elsevier Inc. All rights reserved.)

Fasting chylomicronaemia appears in type V (multifactorial chylomicronaemia syndrome, MCS), and in type I (familial chylomicronaemia syndrome, FCS). MCS needs to be treated as in any general hypertriglyceridaemia: low-calorie diet, avoid sugar and alcohol, reduce body weight, control of diabetes and, in some cases, common lipid lowering-drugs, such as fibrates or omega-3 fatty acids. For type I HLP, FCS, patients should adhere to a strict very low fat diet, usually less than 15-20 g per day. In spite of this, many patients with FCS suffer from recurrent abdominal pain and/or acute pancreatitis. Volanesorsen, an antisense oligonucleotide against apolipoprotein C-III, is the only drug approved to control the disease. As shown in the APPROACH study, the administration of volanesorsen at a weekly dose of 285 mg induced at three month a reduction of triglycerides of 77% (primary end-point) and a reduction of 1712 mg/dL from the baseline. Among patient receiving volanesorsen, 77% reached a fasting triglyceride value below 750 mg/dL. The most frequent side effects were a skin reaction at injection site and low platelet levels, which should be monitored., (Copyright © 2021. Publicado por Elsevier España, S.L.U.)

Background: Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive lipid disorder often associated with recurrent episodes of pancreatitis. It is documented in most cases with FCS due to the mutations of key proteins in lipolysis, including LPL, APOC2, APOA5, LMF1 and GPIHBP1., Case Presentation: We report the successful management of a 35-year-old pregnant woman carrying a novel homozygous frameshift mutation c.48&#95;49insGCGG (p.P17A fs*22) in the GPIHBP1 gene with previous severe episodes of acute pancreatitis triggered by pregnancy, resulting in adverse obstetrical outcomes. With careful monitoring, the patient underwent an uneventful pregnancy and delivered a baby with no anomalies., Conclusions: The case report contributes to the understanding of GPIHBP1-deficient familial chylomicronemia syndrome (FCS) and highlights gestational management of FCS patient.

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., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The chylomicronemia syndrome occurs when triglyceride levels are severely elevated (usually >16.95 mmol/L [1500 mg/dL]) and is characterized by such clinical features as abdominal pain, acute pancreatitis, eruptive xanthomas, and lipemia retinalis. It may result from 1 of 3 conditions: the presence of secondary forms of hypertriglyceridemia concurrent with genetic causes of hypertriglyceridemia, termed multifactorial chylomicronemia syndrome (MFCS); a deficiency in the enzyme lipoprotein lipase and some associated proteins, termed familial chylomicronemia syndrome (FCS); or familial partial lipodystrophy. Most chylomicronemia syndrome cases are the result of MFCS; FCS is very rare. In all these conditions, triglyceride-rich lipoproteins accumulate because of impaired plasma clearance. This review describes the 3 major causes of the chylomicronemia syndrome; their consequences; and the approaches to treatment, which differ considerably by group.

Objective: Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder caused by mutations in lipoprotein lipase, resulting in accumulation of chylomicrons in plasma and hypertriglyceridemia. Elevated triglycerides cause several complications in patients, the most serious being episodes of acute pancreatitis. This review focuses on expert guidance and opinion from an experienced lipidologist and endocrinologist as well as a current review of the literature, as there are no specific guidelines on FCS., Methods: Discussion of expert guidance and opinion review of current literature., Results: To date, there is no pharmacologic treatment for affected patients, and management options primarily include adoption of an extremely restricted, very-low-fat diet, along with avoidance of certain medications and alcohol. Endocrinologists often diagnose and manage patients with metabolic disorders, including patients with high triglyceride levels, but rare diseases like FCS can be missed or poorly evaluated due to knowledge gaps about disease state. Given endocrinologists' role in the treatment of lipid disorders, it is important that they understand the clinical signs and symptoms of FCS to correctly diagnose patients. Patients with FCS can be identified based on a defined clinical criteria and a thorough review of medical history, after excluding differential diagnoses and secondary factors. Typical manifestations include hypertriglyceridemia characterized by lipemic serum, history of abdominal pain, and acute/recurrent pancreatitis. Secondary factors to be excluded are pregnancy, alcohol abuse, uncontrolled diabetes, and use of certain medications., Conclusion: FCS is a rare, inherited lipid disorder disease that often goes underdiagnosed and unmanaged. This review provides a summary of clinical characteristics of FCS that can be potentially used to screen patients in an endocrinologist's office and direct them to the appropriate standard of care., Abbreviations: apoB = apolipoprotein B; apoC-III = apolipoprotein CIII; ASO = antisense oligonucleotide; FCS = familial chylomicronemia syndrome; HTG = hypertriglyceridemia; LPL = lipoprotein lipase; LPLD = lipoprotein lipase deficiency.

One-year results are reported of the first lipoprotein lipase deficiency (LPLD) patient treated with alipogene tiparvovec, which is indicated for the treatment of patients with genetically confirmed LPLD suffering from acute and recurrent pancreatitis attacks (PAs) despite dietary restrictions and expressing >5% of lipoprotein lipase (LPL) mass compared to a healthy control. During clinical development, alipogene tiparvovec has shown improvement of chylomicron metabolism and reduction of pancreatitis incidence up to 5.8 years post treatment. A 43-year-old female presented with severe hypertriglyceridemia (median triglyceride [TG] value of 3,465 mg/dL) and a history of 37 PAs within the last 25 years, despite treatment with fibrates, omega 3 fatty acids, and-since 2012-twice-weekly lipid apheresis. LPLD was confirmed by identification of two different pathogenic variants in the LPL gene located on separate alleles and therefore constituting a compound heterozygous state. With a detectable LPL mass level of 55.1 ng/mL, the patient was eligible for alipogene tiparvovec treatment, and in September 2015, she receved 40 injections (1 × 10 12 genome copies/kg) in the muscles of her upper legs under epidural anesthesia and immunosuppressive therapy. Alipogene tiparvovec was well tolerated: no injection site or systemic reactions were observed. Median TG values decreased by 52%, dropping to 997 mg/dL at month 3 and increasing thereafter. Within the first 18 months post treatment, the patient discontinued plasmapheresis and had no abdominal pain or PAs. In March 2017, the patient suffered from a PA due to diet violation. Within the first 12 months post treatment, overall quality of life improved, and no change in humoral or cellular immune response against LPL or AAV-1 was observed. In conclusion, alipogene tiparvovec was well tolerated, with a satisfactory response to treatment. Long-term effects on the recurrence of pancreatitis continue to be monitored.

Plasma triglyceride concentrations are normally below 150 mg/dL in the fasting state. However, these lipids can reach values of several thousand mg/dL. Elevations in this range are due to a massive retention of chylomicrons and usually result from multiple genetic variants with superimposed influences such as diabetes and immune disorders. Less commonly, major gene defects in lipoprotein metabolism can be the cause. These may present soon after birth with strong evidence of familial penetrance. The causes of this syndrome have been discussed in a Roundtable published in the most recent issue of this Journal. The polygenic etiology may also have a familial presentation with similar clinical import. The diagnosis and management of these disorders is of importance since they can lead to critical clinical syndromes including death from acute hemorrhagic pancreatitis. The chronic management requires a dedicated medical team and a patient committed to an effective regimen. We are joined in this discussion by Dr P. Barton Duell, University of Oregon Health Sciences Center, and Dr Daniel Gaudet of the Université de Montreal, Montreal, Quebec. All have had extensive personal experience in the diagnosis and management of patients with familial chylomicronemia. This Roundtable was recorded on November 11, 2017, during a meeting of the National Lipid Association in New Orleans, Louisiana., (Copyright © 2018 National Lipid Association. Published by Elsevier Inc. All rights reserved.)

Background: Lipoprotein lipase (LPL) deficiency is an autosomal recessive genetic disorder characterized by extreme hypertriglyceridemia, with no cure presently available. The purpose of this study was to test the possibility of using cell therapy to alleviate LPL deficiency., Methods: The LPL coding sequence was cloned into the MSCV retrovirus vector, after which MSCV-hLPL and MSCV (empty construct without LPL coding sequence) virion suspensions were made using the calcium chloride method. A muscle cell line (C2C12), kidney cell line (HEK293T) and pre-adipocyte cell line (3 T3-L1) were transfected with the virus in order to express recombinant LPL in vitro. Finally, each transfected cell line was injected subcutaneously into nude mice to identify the cell type which could secret recombinant LPL in vivo. Control cells were transfected with the MSCV empty vector. LPL activity was analyzed using a radioimmunoassay., Results: After virus infection, the LPL activity at the cell surface of each cell type was significantly higher than in the control cells, which indicates that all three cell types can be used to generate functional LPL. The transfected cells were injected subcutaneously into nude mice, and the LPL activity of the nearby muscle tissue at the injection site in mice injected with 3 T3-L1 cells was more than 5 times higher at the injection sites than at non-injected control sites. The other two types of cells did not show this trend., Conclusion: The subcutaneous injection of adipocytes overexpressing LPL can improve the LPL activity of the adjacent tissue of nude mice. This is a ground-breaking preliminary study for the treatment of LPL deficiency, and lays a good foundation for using cell therapy to correct LPL deficiency.

Background: Familial chylomicronemia syndrome (FCS) is a rare genetic disease that leads to severe hypertriglyceridemia often associated with recurrent episodes of pancreatitis. The recognition and correct diagnosis of the disease is challenging due to its rarity, and to the lack of specificity of signs and symptoms. Lipid experts, endocrinologists, gastroenterologists, pancreatologists, and general practitioners may encounter patients who potentially have FCS. Therefore, cooperation between experts and improved knowledge of FCS is essential in improving the diagnosis. Currently, a consensus on best practice for the diagnosis of FCS is lacking., Methods: Aiming to define a diagnostic algorithm for FCS, a board of European experts was instituted. Such an algorithm for FCS is important to guide practitioners in the diagnosis of suspected FCS and to optimize therapeutic strategies., Results: The multidisciplinary views were merged, leading to a diagnostic algorithm, proposed here., Conclusion: This diagnostic algorithm represents a potentially useful tool to support primary and secondary care practitioners in the recognition of signs and clinical manifestations in individuals potentially affected by FCS., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Hyperlipoproteinemia (HLP) and dyslipidemia (DLP) are of course mainly perceived as diseases of common incidence and are typically seen as the greatest risk factors (RF) in the context of the pandemic of cardiovascular diseases. This is certainly true and HLP or DLP overall affect tens of percents of adults. However we cannot overlook the fact that disorders (mostly congenital) of lipid metabolism exist which, though not formally defined as such, amply satisfy the conditions for classification as rare diseases. Our account only includes a brief overview of the rare HLPs based on the dominant disorder of lipid metabolism, i.e. we shall mention the rare primary forms of hypercholesterolemia, primary forms of hypertriglyceridemia and the rare primary combined forms of HLP. In recent years an amazing progress has been reached relating to these diseases, in particular in the area of exact identification of the genetic defect and the mechanism of defect formation, however each of these diseases would require a separate article, though outside the field of clinical internal medicine. Therefore we shall discuss homozygous familial hypercholesterolemia (FH) in greater depth, partially also the "severe" form of heterozygous FH and in the following part the lipoprotein lipase deficiency; that means, diseases which present an extreme and even fatal risk for their carriers at a young age, but on the other hand, new therapeutic possibilities are offered within their treatment. An internist then should be alert to the suspicion that the described diseases may be involved, know about their main symptoms, where to refer the patient and how to treat them. Also dysbetalipoproteinemia (or type III HLP) will be briefly mentioned. Homozygous FH occurs with the frequency of 1 : 1 000 000 (maybe even more frequently, 1 : 160 000), it is characterized by severe isolated hypercholesterolemia (overall cholesterol typically equal to 15 mmol/l or more), xanthomatosis and first of all by a very early manifestation of a cardiovascular disease. Myocardial infarction is not an exception even in childhood. The therapy is based on high-dose statins, statins in combination with ezetimib and now also newly on PCSK9 inhibitors. Lomitapid and partly also mipomersen hold great promise for patients. LDL apheresis then represents an aggressive form of treatment. Lipoprotein lipase deficiency (type I HLP) is mainly characterized by severe hypertriglyceridemia, serum milky in colour, and xanthomatosis. A fatal complication is acute recurrent pancreatitis. A critical part of the treatment is diet, however it alone is not enough to control a genetic disorder. The only approved treatment is gene therapy. Experimentally, as an "off label" therapy, it is used in case studies with a lomitapid effect. We have our own experience with this experimental therapy. Dysbetalipoproteinemia is a congenital disorder of lipoprotein metabolism, characterized by high cholesterol (CH) and triglyceride (TG) levels. The underlying cause of this disease is the defect of the gene providing for apolipoprotein E. It is clinically manifested by xanthomatosis, however primarily by an early manifestation of atherosclerosis (rather peripheral than coronary).Key words: Lipoprotein lipase deficiency - dysbetalipoproteinemia - familial hypercholesterolemia - gene therapy - homozygous FH - LDL apheresis - lomitapid - mipomersen - PCSK9 inhibitors - rare diseases.

Even though gene therapy made its way through the clinics to treat a number of human pathologies since the early years of experimental research and despite the recent approval of the first gene-based product (Glybera) in Europe, the safe and effective use of gene transfer vectors remains a challenge in human gene therapy due to the existence of barriers in the host organism. While work is under active investigation to improve the gene transfer systems themselves, the use of controlled release approaches may offer alternative, convenient tools of vector delivery to achieve a performant gene transfer in vivo while overcoming the various physiological barriers that preclude its wide use in patients. This article provides an overview of the most significant contributions showing how the principles of controlled release strategies may be adapted for human gene therapy.

Lipoprotein lipase (LPL), a member of the triglyceride lipase gene family, is synthesised by parenchymal cells of the heart, skeletal muscle and adipose tissues before being transported to luminal surfaces of vascular endothelial cells to exert its main physiological function to hydrolyse plasma lipoproteins. LPL deficiency is a rare autosomal recessive disorder, resulting in severe hypertriglyceridaemia from birth. The effect of marked hypertriglyceridaemia on the immune function in children has not been described. We present a case of a neonate with LPL deficiency and grossly elevated plasma triglyceride levels, presenting with recurrent and recalcitrant perianal abscesses suggestive of underlying immunodeficiency. With reduced levels of plasma triglycerides, the recurrent perianal infections resolved. This case report reviews evidence for potential deleterious effects of hypertriglyceridaemia on immune function, however, underlying mechanisms are poorly understood. Whether hypertriglyceridaemia contributes to immune dysfunction in this context is unknown. If there is a pathophysiological link, this may have implications for hypertriglyceridaemia management., (2016 BMJ Publishing Group Ltd.)

During pregnancy physiological changes occur in the lipid metabolism due to changing hormonal conditions: the LDL cholesterol (LDL-C), triglycerides (TG) and lipoprotein(a) [Lp(a)] increase throughout pregnancy. Common lipoprotein disorders are associated in pregnancy with two major clinical disorders: severe hypertriglyceridemia (SHTG) is a potent risk factor for development of acute pancreatitis and elevated cholesterol due to greater concentrations of LDL and remnant lipoproteins and reduced levels of HDL promote atherosclerosis. The combination of homozygous Familial Hypercholesterolemia (HoFH) and pregnancy can be a fatal condition. Therapeutic plasma exchange (TPE) may be used for an urgent need of a fast and effective lowering of TG levels in order to prevent a severe pancreatitis episode or hypertriglyceridemia-induced complications during pregnancy. LDL apheresis can decrease LDL-C and prevent complications and can be considered in the treatment of pregnancies complicated by high LDL-C. These conditions are configured in patients with HeFH who were taking statins before pregnancy (selected cases), patients already receiving apheresis before pregnancy suffering from HoFH, patients suffering from hypertriglyceridemia due to familial hyperlipoproteinemia types I and V, and cases of hypertriglyceridemia secondary to diabetes., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

We present a case of severe acute pancreatitis induced by hypertriglyceridemia secondary to lipoprotein lipase (LPL) deficiency in a pregnant patient with gestational diabetes, initially maneged with diet but it was later necessary to carry out artificial nutricional support measures: total parenteral nutrition. LPL deficiency might cause severe hypertriglyceridemia, repetition acute pancreatitis which is an unwieldy and severe situation during pregnancy. Acute familial hypertriglyceridemia pancreatitis accounts for 5% of cases, including LPL deficiency. The goal of treatment is to reach triglycerides levels below 500 mg/dl, being very low fat diet the treatment of choice, drugs or plasmapheresis techniques can also be associated. TPN enriched in ω3 fatty acids and glutamine was safe and effective in our patient with significant decrease in triglyceride levels., (Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.)

This Review discusses new developments in understanding the basis of chylomicronaemia--a challenging metabolic disorder for which there is an unmet clinical need. Chylomicronaemia presents in two distinct primary forms. The first form is very rare monogenic early-onset chylomicronaemia, which presents in childhood or adolescence and is often caused by homozygous mutations in the gene encoding lipoprotein lipase (LPL), its cofactors apolipoprotein C-II or apolipoprotein A-V, the LPL chaperone lipase maturation factor 1 or glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1. The second form, polygenic late-onset chylomicronaemia, which is caused by an accumulation of several genetic variants, can be exacerbated by secondary factors, such as poor diet, obesity, alcohol intake and uncontrolled type 1 or type 2 diabetes mellitus, and is more common than early-onset chylomicronaemia. Both forms of chylomicronaemia are associated with an increased risk of life-threatening pancreatitis; the polygenic form might also be associated with an increased risk of cardiovascular disease. Treatment of chylomicronaemia focuses on restriction of dietary fat and control of secondary factors, as available pharmacological therapies are only minimally effective. Emerging therapies that might prove more effective than existing agents include LPL gene therapy, inhibition of microsomal triglyceride transfer protein and diacylglycerol O-acyltransferase 1, and interference with the production and secretion of apoC-III and angiopoietin-like protein 3.

Alipogene tiparvovec (Glybera®; AMT-011, AAV1-LPL(S447X)) is an adeno-associated virus serotype 1-based gene therapy for adult patients with familial lipoprotein lipase (LPL) deficiency (LPLD) and suffering from severe or multiple pancreatitis attacks despite dietary fat restrictions. It is administered as a one-time series of intramuscular injections in the legs. LPLD, a rare autosomal recessive disorder, results in hyperchylomicronaemia and severe hypertriglyceridaemia, which in turn, are associated with an increased risk of clinical complications, the most debilitating of which is recurrent severe and potentially life-threatening pancreatitis. In clinical studies (n = 27 patients), one-time administration of alipogene tiparvovec was associated with significant reductions in plasma triglyceride levels during the 12 or 14 week study period post administration. Although triglyceride levels returned to pre-treatment levels within 16-26 weeks after administration, patients had sustained improvements in postprandial chylomicron metabolism, with sustained expression of functional copies of the LPL (S477X) gene and of biologically active LPL in skeletal muscle. Moreover, after up to 6 years' follow-up post administration, there were clinically relevant reductions in the incidence of documented pancreatitis and acute abdominal pain events consistent with pancreatitis. Alipogene tiparvovec was generally well tolerated, with most adverse events being localized, transient, mild to moderate injection-site reactions. This article reviews the pharmacology of alipogene tiparvovec and its efficacy and safety in adults with LPLD.

Cellular immune responses to adeno-associated viral (AAV) vectors used for gene therapy have been linked to attenuated transgene expression and loss of efficacy. The impact of such cellular immune responses on the clinical efficacy of alipogene tiparvovec (Glybera; AAV1-LPL(S447X); uniQure), a gene therapy consisting of intramuscular administration of a recombinant AAV1 mediating muscle-directed expression of lipoprotein lipase (LPL), was investigated. Five subjects with LPL deficiency (LPLD) were administered intramuscularly with a dose of 1 × 10(12) gc/kg alipogene tiparvovec. All subjects were treated with immune suppression starting shortly before administration of alipogene tiparvovec and maintained until 12 weeks after administration. Systemic antibody and T cell responses against AAV1 and LPL(S447X), as well as local cellular immune responses in the injected muscle, were investigated in five LPLD subjects. Long-term transgene expression was demonstrated despite a transient systemic cellular response and a stable humoral immune response against the AAV1 capsid protein. Cellular infiltrates were found in four of the five subjects but were not associated with adverse clinical events or elevation of inflammation markers. Consistent herewith, CD8+ T cells in the infiltrates lacked cytotoxic potential. Furthermore, FoxP3+/CD4+ T cells were found in the infiltrates, suggesting that multiple mechanisms contribute to local tolerance. Systemic and local immune responses induced by intramuscular injection of alipogene tiparvovec did not appear to have an impact on safety and did not prevent LPL transgene expression. These findings support the use of alipogene tiparvovec in individuals with LPLD and indicate that muscle-directed AAV-based gene therapy remains a promising approach for the treatment of human diseases.

There has been great interest over the past two decades in developing gene therapies (GTs) to treat a variety of diseases; however, translating research findings into clinical treatments have proved to be a challenge. A major milestone in the development of GT has been achieved with the approval of alipogene tiparvovec (Glybera(®)) in Europe for the treatment of familial lipoprotein lipase deficiency. At this important stage with the evolution of GT into the clinic, this review will examine the safety aspects GT with adeno-associated virus (AAV) vectors. The topics that will be covered include acute reactions, immunological reactions to the AAV capsid and expressed transgene, viral biodistribution and shedding, DNA integration and carcinogenicity. These safety aspects of GT will be discussed with a focus on alipogene tiparvovec, in addition to other AAV vector GT products currently in clinical development.

Background: Gene therapy, replacing a defective gene by a functional copy, has been in development for more than 40years. Initial efforts involved engineering viral vectors to deliver genes to the appropriate cells. Early successes in severe combined immunodeficiency (SCID) were later derailed by safety issues including host reaction to the vector and gene insertion near promoters that favored secondary leukemia., Methods: Systematic review of the literature using PubMed.gov with key word gene therapy from 1972 to March 2013. Google search with key word gene therapy., Results: Despite early setbacks, progresses for monogenic diseases continued unabated. Patients with SCIDs have been cured and the first gene therapy has been approved for lipoprotein lipase deficiency. Many clinical research studies are ongoing as part of systematic clinical development program with a view to have more gene therapies approved., Conclusion: Our review highlights progresses and questions that remain to be answered to make gene therapy an integral part of our therapeutic arsenal., (© 2013.)

After clearing many hurdles, gene therapy is now reaching the commercialization stage and can be expected to make a modest but real contribution to treatment in the near future., (© 2013 médecine/sciences – Inserm.)

We report the case of a patient who experienced extreme recurrent gestational hyperlipidemia. She was diagnosed with partial lipoprotein lipase (LPL) deficiency but without an associated LPL gene mutation in the presence of the apolipoprotein E3/2 genotype. This is the first reported case of extreme gestational hyperlipidemia with a partial LPL deficiency in the absence of an LPL gene mutation and the apolipoprotein E 3/2 genotype. She was managed with strict dietary control and medicated with omega-3 acid ethyl esters. A patient with extreme hyperlipidemia that is limited to the gestational period should be considered partially LPL-deficient. Extreme instances of hyperlipidemia increase the risk of acute pancreatitis, and the effect of parturition on declining plasma lipid levels can be immediate and dramatic. Therefore, decisions regarding the timing and route of delivery with extreme gestational hyperlipidemia are critical and should be made carefully.

Primary hyperchylomicronemia is characterized by a marked hypertriglyceridemia due to an increase in chylomicrons, which may cause acute pancreatitis and eruptive xanthomas. This entity includes familial lipoprotein lipase (LPL) deficiency, familial apolipoprotein C-II deficiency, primary type V hyperlipoproteinemia, and idiopathic hyperchylomicronemia. Idiopathic hyperchylomicronemia is caused by an LPL inhibitor or autoantibody against LPL. More recently, patients with primary hyperchylomicronemia caused by mutations in the gene for glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1(GPIHBP1) or lipase maturation factor 1(LMF1). For the treatment of primary hyperchylomicronemia, a strict restriction of dietary fat is essential to avoid acute pancreatitis.

The role of lipid lowering in reducing the risk of mortality and morbidity from cardiovascular disease (CVD) is well established. Treatment particularly aimed at decreasing low-density lipoprotein cholesterol (LDL-C) is effective in reducing the risk of death from coronary heart disease and stroke. Statins form the cornerstone of treatment. However, in some individuals with a high risk of CVD who are unable to achieve their target LDL-C due to either intolerance or lack of efficacy, there is the need for alternative therapies. This review provides an overview of the different classes of currently available lipid-lowering medications including statins, fibrates, bile acid sequestrants (resins), and omega-3 fatty acids. Data are presented on their indications, pharmacology, and the relevant end point clinical trial data with these drugs. It also discusses the human trial data on some novel therapeutic agents that are being developed including those for homozygous familial hypercholesterolemia--the antisense oligonucleotide mipomersen and the microsomal transfer protein inhibitor lomitapide. Data are presented on phase II and III trials on agents with potentially wider applications, cholesterol ester transfer protein inhibitors and proprotein convertase subtilisin kexin 9 inhibitors. The data on a licensed gene therapy for lipoprotein lipase deficiency are also presented.

We describe the 2-year follow-up of an open-label trial (CT-AMT-011-01) of AAV1-LPL(S447X) gene therapy for lipoprotein lipase (LPL) deficiency (LPLD), an orphan disease associated with chylomicronemia, severe hypertriglyceridemia, metabolic complications and potentially life-threatening pancreatitis. The LPL(S447X) gene variant, in an adeno-associated viral vector of serotype 1 (alipogene tiparvovec), was administered to 14 adult LPLD patients with a prior history of pancreatitis. Primary objectives were to assess the long-term safety of alipogene tiparvovec and achieve a ≥40% reduction in fasting median plasma triglyceride (TG) at 3-12 weeks compared with baseline. Cohorts 1 (n=2) and 2 (n=4) received 3 × 10(11) gc kg(-1), and cohort 3 (n=8) received 1 × 10(12) gc kg(-1). Cohorts 2 and 3 also received immunosuppressants from the time of alipogene tiparvovec administration and continued for 12 weeks. Alipogene tiparvovec was well tolerated, without emerging safety concerns for 2 years. Half of the patients demonstrated a ≥40% reduction in fasting TG between 3 and 12 weeks. TG subsequently returned to baseline, although sustained LPL(S447X) expression and long-term changes in TG-rich lipoprotein characteristics were noted independently of the effect on fasting plasma TG.

Background: The treatment of familial hyperchylomicronemia presenting in early childhood with episodes of pancreatitis has been ineffective, and affected patients remain at risk for pancreatitis., Objective: To report on the effect of orlistat in siblings with severe inherited hyperchylomicronemia and to assess posttreatment lipoprotein concentrations and composition., Methods: Serial observations of plasma lipid levels and hospitalizations after treatment with orlistat and lipoprotein studies on a single fasting posttreatment sample., Results: The affected siblings inherited a lipoprotein lipase gene mutation from each of their parents: a novel mutation from their father (c.542G > C, p.G181R) and a known missense mutation from their mother (c.644G > A, p.G215E). When the boy presented to us at age 9 years of age and his sister at age 7 years, we found that addition of orlistat, a pancreatic lipase inhibitor, at a dose of 120 mg given before three low-fat meals a day was effective in reducing episodes of pancreatitis in the boy and in maintaining the triglyceride at lower levels in both children. During treatment, the children were observed to have elevations in apolipoprotein (apo)B, low-density lipoprotein particle concentration, abnormal apoB-containing subclasses, and deficiencies in apoA-I and apoA-II-containing lipoproteins, changes consistent with continuing increased cardiovascular risk., Conclusion: The data support the need for more effective long-term treatments that not only prevent pancreatitis but also offset cardiovascular risk. Orlistat can be considered effective in augmenting the effect of a low-fat diet and reducing risk for pancreatitis., (Copyright © 2013 National Lipid Association. Published by Elsevier Inc. All rights reserved.)

Alipogene tiparvovec is the first adeno-associated virus (AAV)-mediated gene therapy to be approved for the treatment of a metabolic disorder. Lipoprotein lipase (LPL) deficiency (LPLD) is a rare autosomal-recessive disorder in which gene mutations cause the production of a catalytically inactive enzyme required for plasma triglyceride hydrolysis. The resultant hypertriglyceridemia causes frequent abdominal pain, fatty deposits in the skin and retina, and can lead to potentially fatal pancreatitis. In addition, patients with LPLD can develop diabetes and cardiovascular disease. Past therapies to lower plasma triglycerides in these patients have been ineffective. Intramuscular injection of alipogene tiparvovec delivers a natural gain-of-function LPL gene variant, LPLS447X, to muscle tissue and has demonstrated efficacy in animal models of LPLD. In phase I/II and phase II/III clinical evaluations, alipogene tiparvovec significantly lowered plasma triglycerides and increased LPL activity, resulting in a reduction in plasma chylomicron and a decrease in the frequency of pancreatitis episodes. The therapy is well tolerated in animals and humans and produces no serious treatment-related adverse effects., (Copyright 2013 Prous Science, S.A.U. or its licensors. All rights reserved.)