Severe hypertriglyceridemia as a cause of necrotizing pancreatitis in a pediatric patient with familial hyperchylomicronemia syndrome: A case report.

Familial hyperchylomicronemia syndrome is a monogenic autosomal recessive disorder that causes severe and refractory hypertriglyceridemia. This uncommon condition is challenging to diagnose and treat and can lead to comorbidities such as acute pancreatitis. Although treatment options are limited in the pediatric population, strict diets and treatments approved for other dyslipidemias may be implemented in familial hyperchylomicronemia syndrome, given the lack of pharmacological interventions available. We report a 14-year-old female presented to the emergency room with abdominal pain suggestive of acute pancreatitis. Biochemical analysis revealed a triglyceride value of 4260 mg/dL. Treatment for triglyceride reduction with a strict CHILD-2 triglyceride-lowering diet, insulin infusion, fibrates, and multiple plasmapheresis were initially insufficient. Primary hypertriglyceridemia was suspected, and genetic testing identified a homozygous pathogenic variant in the lipoprotein lipase gene, diagnosing familial hyperchylomicronemia syndrome. She was discharged with a maximum dose of fibrate, statin, omega-3 fatty acids, and a restrictive diet. At her 1-month and 9-month follow-ups, her triglyceride values were 756 and 495 mg/dL, respectively, without incident complications. Familial hyperchylomicronemia syndrome is an uncommon condition with limited available literature and treatment options, especially in the pediatric population. Acute pancreatitis secondary to severe hypertriglyceridemia is a condition with a high risk of mortality which requires prompt clinical suspicion and treatment.

Early myocardial functional abnormalities in primary dyslipidemia: clinical and echocardiographic observations in young children from a highly consanguineous population.

BACKGROUND: Dyslipidemia is a major health problem among children and adolescents worldwide due to its significant association with cardiovascular disease. Primary dyslipidemias are commonly familial syndromes that can be completely asymptomatic. PURPOSE: Apart from the risk of coronary artery disease (CAD), limited data are currently available on the direct effects of dyslipidemia on myocardial function in children. METHODS: We recruited 25 children with primary dyslipidemia (14 with isolated hypercholesterolemia, 4 with isolated hypertriglyceridemia, and 7 with combined dyslipidemia). Relevant clinical manifestations and laboratory and radiological investigations were evaluated. Pulsed-wave Doppler and tissue Doppler imaging echocardiography were performed for all recruited patients and the results were compared with those of 15 age- and sex-matched healthy children. RESULTS: The median age of the dyslipidemic children was 8 years (range, 1.5-16 years). A family history was documented in 13 cases (52%), while 18 (72%) had consanguineous parents. None of the dyslipidemic children had a personal history or clinical manifestations of CAD. In contrast, echocardiographic findings differed in several diastolic function parameters of both right and left ventricles in dyslipidemic children compared to controls. Based on normalized z scores, aortic valve narrowing was detected in 7 patients (28%), while narrowing of the aortic sinus (sinus of Valsalva) was detected in 15 patients (60%). CONCLUSION: Different types of primary dyslipidemia produce functional myocardial abnormalities early in childhood. Biochemical and echocardiographic screening of high-risk children is advised to minimize the incidence of serious cardiovascular complications.

Epidemiology of familial hypercholesterolaemia: Community and clinical.

Familial hypercholesterolaemia (FH) is a genetic disorder affecting the metabolism of low-density lipoprotein (LDL) particles, leading to high LDL-cholesterol levels maintained over time and higher risk of cardiovascular disease (CVD) early in life. Contemporary studies have challenged prior estimations of FH prevalence and suggest this condition to be more frequent than previously considered, with an overall prevalence rate of 1:200-300 individuals in the general population (1:160,000-300,000 for homozygous FH). However, prevalence of FH varies around the world. In part this is due to an artefact of approaches of detection and methods used to diagnose FH (e.g. lack of gold standard for diagnosis of FH, different criteria applied, availability of genetic testing). But also due to intrinsic characteristic of different populations, e.g. higher presence of founder effects or rates of consanguinity. Additionally, results from many regions are lacking and it is estimated that only a small percentage of subjects with FH would have been diagnosed overall. FH entails a significantly higher risk of CVD, reported to be higher than that estimated by conventional risk assessment tools for the general population. This risk is mainly driven by coronary heart disease. Despite this evidence, low rates of patients meet therapeutic targets for cardiovascular prevention, and implementation of therapy (high intensity statins, combination therapy) is needed. The introduction of novel lipid-lowering therapies may improve this situation. In the present review, we discuss the epidemiology of FH overall, with special attention to different aspects related to prevalence, cardiovascular risk and prognosis, and treatment of FH.

Mining the genome for lipid genes.

Mining of the genome for lipid genes has since the early 1970s helped to shape our understanding of how triglycerides are packaged (in chylomicrons), repackaged (in very low density lipoproteins; VLDL), and hydrolyzed, and also how remnant and low-density lipoproteins (LDL) are cleared from the circulation. Gene discoveries have also provided insights into high-density lipoprotein (HDL) biogenesis and remodeling. Interestingly, at least half of these key molecular genetic studies were initiated with the benefit of prior knowledge of relevant proteins. In addition, multiple important findings originated from studies in mouse, and from other types of non-genetic approaches. Although it appears by now that the main lipid pathways have been uncovered, and that only modulators or adaptor proteins such as those encoded by LDLRAP1, APOA5, ANGPLT3/4, and PCSK9 are currently being discovered, genome wide association studies (GWAS) in particular have implicated many new loci based on statistical analyses; these may prove to have equally large impacts on lipoprotein traits as gene products that are already known. On the other hand, since 2004 - and particularly since 2010 when massively parallel sequencing has become de rigeur - no major new insights into genes governing lipid metabolism have been reported. This is probably because the etiologies of true Mendelian lipid disorders with overt clinical complications have been largely resolved. In the meantime, it has become clear that proving the importance of new candidate genes is challenging. This could be due to very low frequencies of large impact variants in the population. It must further be emphasized that functional genetic studies, while necessary, are often difficult to accomplish, making it hazardous to upgrade a variant that is simply associated to being definitively causative. Also, it is clear that applying a monogenic approach to dissect complex lipid traits that are mostly of polygenic origin is the wrong way to proceed. The hope is that large-scale data acquisition combined with sophisticated computerized analyses will help to prioritize and select the most promising candidate genes for future research. We suggest that at this point in time, investment in sequence technology driven candidate gene discovery could be recalibrated by refocusing efforts on direct functional analysis of the genes that have already been discovered. This article is part of a Special Issue entitled: From Genome to Function.