Long-term effects of volanesorsen on triglycerides and pancreatitis in patients with familial chylomicronaemia syndrome (FCS) in the UK Early Access to Medicines Scheme (EAMS).

BACKGROUND AND AIMS: The VOL4002 study assessed the efficacy and safety of volanesorsen in 22 adults with genetically confirmed familial chylomicronaemia syndrome (FCS) treated in the UK Early Access to Medicines Scheme (EAMS), with ("prior exposure") or without ("treatment naive") previous treatment in the APPROACH and/or APPROACH-OLE volanesorsen phase 3 studies. METHODS: Data collection focused on triglyceride (TG) levels, platelet counts and pancreatitis events. Pancreatitis incidence during volanesorsen treatment was compared against the 5-year period preceding volanesorsen exposure. Volanesorsen 285 mg was self-administered subcutaneously once every 2 weeks. RESULTS: Individual patient volanesorsen exposure ranged from 6 to 51 months (total cumulative exposure, 589 months). Among treatment-naive patients (n = 12), volanesorsen treatment resulted in an averaged median 52% reduction (-10.6 mmol/L) from baseline (26.4 mmol/L) in TG levels at 3 months, which were maintained through time points over 15 months of treatment (47%-55% reductions). Similarly, prior-exposure patients (n = 10) experienced a 51% reduction (-17.8 mmol/L) from pre-treatment baseline (28.0 mmol/L), with reductions of 10%-38% over 21 months of treatment. A comparison of pancreatitis event rates found a 74% reduction from the 5-year period before (one event/2.8 years) and during (one event/11.0 years) volanesorsen treatment. Platelet declines were consistent with observations in phase 3 clinical trials. No patient recorded a platelet count <50 × 109/L. CONCLUSIONS: This longitudinal study supports the efficacy of volanesorsen in patients with FCS for lowering TG levels over treatment periods up to 51 months with no apparent safety signals related to increased duration of exposure.

Rare Variants in Triglycerides-Related Genes Increase Pancreatitis Risk in Multifactorial Chylomicronemia Syndrome.

CONTEXT: Severe hypertriglyceridemia (fasting triglycerides [TG] concentration ≥10 mmol/L) can be caused by multifactorial chylomicronemia syndrome (MCS) or familial chylomicronemia syndrome (FCS). Both conditions are associated with an increased risk of acute pancreatitis. The clinical differences between MCS patients with or without a rare variant in TG-related genes have never been studied. OBJECTIVE: To compare the clinical and biochemical characteristics of FCS, positive-MCS patients, and negative-MCS patients, as well as to investigate the predictors of acute pancreatitis in MCS patients. METHODS: All patients referred at the clinic for severe hypertriglyceridemia underwent genetic testing for the 5 canonical genes involved in TG metabolism (LPL, APOC2, GPIHBP1, APOA5, and LMF1) using next-generation sequencing. RESULTS: A total of 53 variant negative-MCS, 22 variant positive-MCS and 28 FCS subjects were included in this retrospective cross-sectional study. A significant difference was observed in the prevalence of pancreatitis (9%, 41%, and 61%) and multiple pancreatitis (6%, 23%, and 46%) in the negative-MCS, the positive-MCS, and the FCS groups, respectively (P < 0.0001). Predictors of pancreatitis among MCS subjects included the presence of a rare variant, lower apolipoprotein B, as well as higher gamma-glutamyl transferase, maximal TG value, and fructose consumption. CONCLUSION: We observed that the MCS individuals who carried a rare variant have an intermediate phenotype between FCS and negative-MCS subjects. Since novel molecules such as the antisense oligonucleotide against APOC3 mRNA showed high efficacy in reducing TG levels in patients with multifactorial chylomicronemia, identification of higher-risk MCS patients who would benefit from additional treatment is essential.

Efficacy and safety of volanesorsen in patients with multifactorial chylomicronaemia (COMPASS): a multicentre, double-blind, randomised, placebo-controlled, phase 3 trial.

BACKGROUND: Volanesorsen is an antisense oligonucleotide that targets hepatic apolipoprotein C-III synthesis and reduces plasma triglyceride concentration. The aim of this study was to explore the safety and efficacy of volanesorsen in patients with multifactorial chylomicronaemia syndrome. METHODS: The COMPASS trial was a randomised, placebo-controlled, double-blind, phase 3 study done at 38 international clinical sites in Canada, France, Germany, the Netherlands, UK, and USA. Eligible patients were aged 18 years or older with multifactorial severe hypertriglyceridaemia or familial chylomicronaemia syndrome, who had a BMI of 45 kg/m2 or less and fasting plasma triglyceride of 500 mg/dL or higher. Patients were randomly assigned (2:1) with an interactive response system using an allocation sequence and permuted block randomisation to receive subcutaneous volanesorsen (300 mg) or a matched volume of placebo (1·5 mL) once a week for 26 weeks. After 13 weeks of treatment, dosing was changed to 300 mg of volanesorsen or placebo every 2 weeks for all patients, except those who had completed 5 months or more of treatment as of May 27, 2016. Participants, investigators, sponsor personnel, and clinical research staff were all masked to the treatment assignments. The primary outcome was percentage change from baseline to 3 months in fasting triglyceride in the full analysis set (all patients who were randomly assigned and received at least one dose of study drug and had a baseline fasting triglyceride assessment). This trial is registered with ClinicalTrials.gov, NCT02300233 (completed). FINDINGS: Between Feb 5, 2015, and Jan 24, 2017, 408 patients were screened for eligibility. 294 were excluded and 114 randomly assigned to receive either volanesorsen (n=76) or placebo (n=38). One patient in the volanesorsen group discontinued before receiving the study drug. The total number of dropouts was 28 (four in the placebo group and 24 in the treatment group). Volanesorsen reduced mean plasma triglyceride concentration by 71·2% (95% CI -79·3 to -63·2) from baseline to 3 months compared with 0·9% (-13·9 to 12·2) in the placebo group (p<0·0001), representing a mean absolute reduction of fasting plasma triglycerides of 869 mg/dL (95% CI -1018 to -720; 9·82 mmol/L [-11·51 to -8·14]) in volanesorsen compared with an increase in placebo of 74 mg/dL (-138 to 285; 0·83 mmol/L [-1·56 to 3·22]; p<0·0001). In the key safety analysis, five adjudicated events of acute pancreatitis occurred during the study treatment period, all in three of 38 patients in the placebo group. The most common adverse events were related to tolerability and included injection-site reactions (average of 24% of all volanesorsen injections vs 0·2% of placebo injections), which were all mild or moderate. One participant in the volanesorsen group had a platelet count reduction to less than 50 000 per µL and one patient had serum sickness, both of which were regarded as serious adverse events. INTERPRETATION: Volanesorsen significantly reduced triglyceride concentrations in patients with multifactorial chlyomicronaemia and might reduce acute pancreatitis events in these patients. FUNDING: Ionis Pharmaceuticals and Akcea Therapeutics.

THE PREVALENCE OF PROBABLE FAMILIAL CHYLOMICRONEMIA SYNDROME IN A SOUTHERN CALIFORNIA POPULATION.

OBJECTIVE: To estimate the prevalence of probable familial chylomicronemia syndrome (FCS) in a major Southern California Academic Center as well as to provide a systematic review of past FCS studies and management recommendations. METHODS: Electronic medical records were queried based on single fasting plasma triglyceride (TG) levels of ≥880 mg/dL and at least 1 episode of acute pancreatitis. After the exclusion of secondary causes (diabetes, alcohol misuse, gallbladder disease, chronic kidney disease, uncontrolled hypothyroidism, estrogen, and drug use) and responses to lipid-lowering treatment, probable patients with FCS were identified. A systematic review of all published literature on the prevalence and management guidelines for FCS was then presented and discussed. RESULTS: Out of 7 699 288 charts queried, 138 patients with TG levels of ≥880 mg/dL and documented evidence of at least 1 episode of acute pancreatitis were identified. Nine patients did not have any documented secondary causes of chylomicronemia. Four of the 9 patients had >20% decrease in TG levels after lipid-lowering treatment, 2 patients were not responsive to lipid-lowering medication, and data on lipid-lowering medications were missing in 3 patients. CONCLUSION: Our study estimates the prevalence of probable FCS at a range of 0.26 to 0.66 per million. Using the recommended criteria, probable FCS cases can be identified to allow early diagnosis and management.

10-Year Comparative Follow-up of Familial versus Multifactorial Chylomicronemia Syndromes.

CONTEXT: The relative incidence of acute pancreatitis, ischemic cardiovascular disease, and diabetes in hyperchylomicronemic patients exhibiting familial chylomicronemia syndrome (FCS) or multifactorial chylomicronemia syndrome (MCS) is unknown. OBJECTIVE: The objective was to study the occurrence of these events in FCS and MCS patients compared with the general population. METHODS: Twenty-nine FCS and 124 MCS patients, with genetic diagnosis, in 4 lipid clinics were matched with 413 controls. Individual hospital data linked to the national claims database were collected between 2006 and 2016. The occurrence of complications was retrospectively assessed before follow-up and during a median follow-up time of 9.8 years, for 1500 patient years of follow-up. RESULTS: Patients with FCS were younger than those with MCS (34.3 ±â€…13.6 vs 45.2 ±â€…12.6 years, P < 0.01). During the study period, 58.6% of the FCS patients versus 19.4% of the MCS patients had at least 1 episode of acute hypertriglyceridemic pancreatitis (AHP) (hazard ratio [HR] = 3.6; P < 0.01). Conversely, the ischemic risk was lower in FCS than in MCS (HR = 0.3; P = 0.05). The risk of venous thrombosis was similar in both groups. The incidence of diabetes was high in both groups compared with matched controls (odds ratio [OR] = 22.8; P < 0.01 in FCS and OR = 30.3; P < 0.01 in MCS). CONCLUSION: The incidence of AHP was much higher in FCS than in MCS patients, whereas the incidence of ischemic cardiovascular events was found to be increased in MCS versus FCS patients and a representative matched control group. Differences in both triglyceride-rich lipoproteins metabolism and comorbidities in MCS versus FCS drive the occurrence of different patterns of complications.

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.

The burden of familial chylomicronemia syndrome in Canadian patients.

BACKGROUND: Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder characterized by persistent extreme hypertriglyceridemia as a result of lipoprotein lipase deficiency. Canada is an important region for FCS research due to the high prevalence rates. The burden of illness and quality of life of Canadian patients, however, have been inadequately addressed in the literature. OBJECTIVE: To understand the burden of illness of FCS on Canadian patients' lives. METHODS: IN-FOCUS is a global web-based survey open to patients with FCS, including patients in Canada. This survey captured information on diagnostic experience, symptoms, comorbidities, disease management, and impact on multiple life dimensions. RESULTS: A total of 37 Canadian patients completed the IN-FOCUS survey. Patients saw a mean of 4 physicians before their FCS diagnosis despite 89% reporting an FCS family history. Patients experience multiple physical, emotional, and cognitive symptoms in addition to FCS-related comorbidities. Notably, 35% of those who answered the survey have experienced acute pancreatitis, averaging 14 lifetime episodes per patient. In the preceding 12 months, 46% of patients had an FCS-related hospitalization, averaging 3 nights' stay. All respondents restricted fat intake, with 27% following an extremely low-fat diet. Despite this, 100% of patients reported fasting TG levels above the normal range. FCS impacted career choice in nearly all patients (97%) and employment status in all patients who were employed part time, disabled, or homemakers, causing many (> 75%) to choose careers below their level of abilities. Furthermore, 2/3 of patients reported FCS had a significant impact on their decision regarding whether to have children. Most report significant interference with their emotional/mental well-being, social relationships, and the majority were concerned about the long-term impact of FCS on their health (89%). CONCLUSIONS: This study provides the first and largest study to investigate the multi-faceted psychosocial and cognitive impacts of FCS on patients. Canadian patients with FCS experience significant multi-faceted burdens that diminish their quality of life, employment opportunities, social relationships, and mental/emotional well-being. These results highlight the need for greater disease awareness, improved clinical diagnosis, broader clinical management for heterogenous symptoms, and more effective treatment options for FCS.

Identifying Perceptions and Preferences of the General Public Concerning Universal Screening of Children for Familial Hypercholesterolaemia.

BACKGROUND/AIMS: Familial hypercholesterolaemia (FH) is a common genetic disorder that, if untreated, predisposes individuals to premature coronary heart disease. As most individuals with FH remain undiagnosed, new approaches to detection are needed and should be considered a priority in public health genomics. Universal screening of children for FH has been proposed, and this study explores public perspectives on the acceptability of this approach. METHODS: A one-day deliberative public forum was held in Perth, WA, Australia. Thirty randomly selected individuals were recruited, with self-reported sociodemographic characteristics used to obtain discursive representation. Participants were presented with information from a variety of perspectives and asked to discuss the information provided to identify points of consensus and disagreement. The data collected were analysed using thematic analysis. RESULTS: Of the 17 participants at the forum, 16 deemed universal screening of children for FH to be acceptable. Fifteen of these 16 believed this was best performed at the time of an immunisation. Participants proposed a number of conditions that should be met to reduce the likelihood of unintended harm resulting from the screening process. DISCUSSION/CONCLUSION: The outcomes of the forum suggest that establishing a universal screening programme for FH in childhood is acceptable to the general public in WA.

Molecular basis of the familial chylomicronemia syndrome in patients from the National Dyslipidemia Registry of the Spanish Atherosclerosis Society.

BACKGROUND: Familial chylomicronemia syndrome (FCS) is an extremely rare lipoprotein disorder caused by mutations in at least 5 genes of the lipoprotein lipase (LPL) complex. OBJECTIVE: This work shows the molecular analysis of patients diagnosed with FCS, who attended the Spanish Arteriosclerosis Society lipid units and were included in the National Dyslipidemia Registry. METHODS: Among the 238 patients registered with severe hypertriglyceridemia (fasting triglycerides >1000 mg/dL), 26 were diagnosed with FCS as they had confirmed postheparin plasma LPL activity deficiency and/or homozygosity for loss-of-function mutations in LPL, GPIHBP1, APOC2, LMF1, or Apolipoprotein A5 (APOA5). RESULTS: Among the 26 FCS cases, 23 had mutations in the homozygous state: 19 in LPL and 4 in the GPIHBP1 gene. The molecular analysis revealed 3 novel mutations: 2 in LPL, in 2 unrelated patients (c.312delA; p.Asp105Thrfs*66 and c.629A>G; p.His210Arg), and 1 in GPHIBP1 in a third patient (c.502delC; p.Leu168Serfs*83). These 3 patients had confirmed lack of LPL activity. Three additional patients with confirmed LPL activity deficiency were heterozygous carriers of mutations in the genes analyzed. Among these, we found 2 novel mutations in APOA5 (c.50-1G>A and c.326_327insC; p.Tyr110Leufs*158). CONCLUSION: We have identified 5 novel pathogenic mutations: 2 in LPL, 1 in GPIHBP1, and 2 in the APOA5 gene. The genetic defaults accounting for the LPL activity deficiency of 23 of them have been clearly identified and 3 patients, who harbored mutations in heterozygosity, were diagnosed based on LPL activity deficiency, which raises the question of the involvement of new genes in the manifestation of FCS.

Chylomicronemia risk factors ranked by importance for the individual and community in 108 711 women and men.

BACKGROUND: Hypertriglyceridemia prevalence is increasing as more individuals become obese, and chylomicronemia risk factors for the individual and community have not been described previously. OBJECTIVE: To describe chylomicronemia risk factors in the general population for individuals and community. METHODS: A total of 108 711 individuals from the Copenhagen General Population Study were grouped as unlikely chylomicronemia (nonfasting triglycerides <2 mmol L-1 (177 mg dL-1 )), possible chylomicronemia (2-4.99 mmol L-1 (177-442 mg dL-1 )), probable chylomicronemia (5-9.99 mmol L-1 (443-885 mg dL-1 )) and definite chylomicronemia (≥10 mmol L-1 (≥ 886 mg dL-1 )). Relative risk (RR) from Poisson regression ranked dichotomized chylomicronemia risk factors for individuals, and population attributable fractions (PAF) for the community: type 2 diabetes, alcohol intake, obesity, fat intake, hypothyroidism, kidney function, education, sedentary lifestyle, menopause and hormone replacement (women). RESULTS: For women and men, chylomicronemia was unlikely in 81% and 64%, possible in 18% and 33%, probable in 1% and 3% and definite in 0.03% and 0.14%, respectively. For the individual, the three top-ranked risk factors for probable/definite versus unlikely chylomicronemia in women were type 2 diabetes (RR: 4.21; 95% confidence interval: 3.30-5.36), menopause (RR: 3.74; 2.62-5.36) and obesity (RR: 3.44; 2.81-4.21). Corresponding top-ranked risk factors in men were obesity (RR: 3.86; 3.46-4.30), type 2 diabetes (RR: 1.88; 1.61-2.19) and reduced kidney function (RR: 1.86; 1.48-2.34). For the community, top-ranked risk factors in women were menopause (PAF: 63%), obesity (PAF: 29%) and type 2 diabetes (PAF: 15%). Corresponding top-ranked risk factors in men were obesity (PAF: 29%), type 2 diabetes (PAF: 6.4%) and sedentary lifestyle (PAF: 6.0%). CONCLUSIONS: Obesity and type 2 diabetes were the most important modifiable chylomicronemia risk factors in women and men, both for the individual and community. This could influence chylomicronemia prevention and help design randomized trials aimed at reducing triglycerides.

The role of registries in rare genetic lipid disorders: Review and introduction of the first global registry in lipoprotein lipase deficiency.

A good understanding of the natural history of rare genetic lipid disorders is a pre-requisite for successful patient management. Disease registries have been helpful in this regard. Lipoprotein Lipase Deficiency (LPLD) is a rare, autosomal-recessive lipid disorder characterized by severe hypertriglyceridemia and a very high risk for recurrent acute pancreatitis, however, only limited data are available on its natural course. Alipogene tiparvovec (Glybera®) is the first gene therapy to receive Marketing Authorization in the European Union; GENIALL (GENetherapy In the MAnagement of Lipoprotein Lipase Deficiency), a 15-year registry focusing on LPLD was launched in 2014 as part of its Risk Management Plan. The aim of this publication is to introduce the GENIALL Registry within a structured literature review of registries in rare genetic lipid disorders. A total of 11 relevant initiatives/registries were identified (homozygous Familial Hypercholesterolemia (hoFH) [n = 5]; LPLD [n = 1]; Lysosomal Acid Lipase Deficiency [LALD, n = 1], detection of mutations in genetic lipid disorders [n = 4]). Besides one product registry in hoFH and the LALD registry, all other initiatives are local or country-specific. GENIALL is the first global prospective registry in LPLD that will collect physician and patient generated data on the natural course of LPLD, as well as long-term outcomes of gene therapy. CONCLUSION: There is a limited number of international initiatives focusing on the natural course of specific rare genetic lipid disorders. The GENIALL LPLD Registry could be the first step towards a future broader global initiative that collects data related to familial chylomicronemia syndrome and their underlying genetic causes.

Prognosis of Patients With Familial Hypercholesterolemia After Acute Coronary Syndromes.

BACKGROUND: Patients with heterozygous familial hypercholesterolemia (FH) and coronary heart disease have high mortality rates. However, in an era of high-dose statin prescription after acute coronary syndrome (ACS), the risk of recurrent coronary and cardiovascular events associated with FH might be mitigated. We compared coronary event rates between patients with and without FH after ACS. METHODS: We studied 4534 patients with ACS enrolled in a multicenter, prospective cohort study in Switzerland between 2009 and 2013 who were individually screened for FH on the basis of clinical criteria according to 3 definitions: the American Heart Association definition, the Simon Broome definition, and the Dutch Lipid Clinic definition. We used Cox proportional models to assess the 1-year risk of first recurrent coronary events defined as coronary death or myocardial infarction and adjusted for age, sex, body mass index, smoking, hypertension, diabetes mellitus, existing cardiovascular disease, high-dose statin at discharge, attendance at cardiac rehabilitation, and the GRACE (Global Registry of Acute Coronary Events) risk score for severity of ACS. RESULTS: At the 1-year follow-up, 153 patients (3.4%) had died, including 104 (2.3%) of fatal myocardial infarction. A further 113 patients (2.5%) experienced nonfatal myocardial infarction. The prevalence of FH was 2.5% with the American Heart Association definition, 5.5% with the Simon Broome definition, and 1.6% with the Dutch Lipid Clinic definition. Compared with patients without FH, the risk of coronary event recurrence after ACS was similar in patients with FH in unadjusted analyses, although patients with FH were >10 years younger. However, after multivariable adjustment including age, the risk was greater in patients with FH than without, with an adjusted hazard ratio of 2.46 (95% confidence interval, 1.07-5.65; P=0.034) for the American Heart Association definition, 2.73 (95% confidence interval, 1.46-5.11; P=0.002) for the Simon Broome definition, and 3.53 (95% confidence interval, 1.26-9.94; P=0.017) for the Dutch Lipid Clinic definition. Depending on which clinical definition of FH was used, between 94.5% and 99.1% of patients with FH were discharged on statins and between 74.0% and 82.3% on high-dose statins. CONCLUSIONS: Patients with FH and ACS have a >2-fold adjusted risk of coronary event recurrence within the first year after discharge than patients without FH despite the widespread use of high-intensity statins.

Molecular-genetic aspects of familial hypercholesterolemia.

Familial hypercholesterolemia (FH) is the world's most abundant and the most common heritable disorder of lipid metabolism. The prevalence of the disease in general population is 1:500. Therefore the approximate number of FH patients all over the world is 14 million. From the genetic point of view the disease originates as a result of mutations in genes affecting the processing of LDL particles from circulation, resulting in an increase in LDL cholesterol and hence total cholesterol. These are mutations in genes encoding LDL receptor, apolipoprotein B, proprotein convertase subtilisin/kexin 9 and LDL receptor adaptor protein 1. Cholesterol depositing in tissues and blood vessels of individuals creates tendon xanthoma, xanthelesma and arcus lipoides cornae. Due to the increased deposition of cholesterol in blood vessels, atherosclerosis process is accelerated, what leads to a significantly higher risk of premature cardiovascular diseases. Therefore, early clinical diagnosis confirmed by the DNA analysis, and effective treatment are crucial to reduce the mortality and high risk of premature atherosclerotic complications.

[Eating my hat?]. / Un chapeau pour mon repas ?

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.

Resequencing CETP, LIPC and LIPG genes in Thai subjects with hyperalphalipoproteinemia.

Genetic factors associated with hyperalphalipoproteinemia (HALP; or high levels of high-density lipoprotein cholesterol) are incompletely understood. The aim of this study was to resequence 3 candidate genes, CETP, LIPC, and LIPG, which encode cholesteryl ester transfer protein, hepatic lipase, and endothelial lipase, respectively, in Thai subjects with HALP and compare them to normolipidemic controls. Sequence variants of CETP, LIPC, and LIPG were identified by sequencing exons and exon-intron junctions in 64 subjects with high-density lipoprotein cholesterol levels ≥2.59 mmol/L (100 mg/dl) and compared to those of 113 normolipidemic subjects. Two heterozygous frameshift mutations in CETP (p.Leu262ProfsX31 and p.Val411ArgfsX6) and two heterozygous missense mutations in LIPC (p.Gly141Ser and p.Val173Met) were found. One deletion mutation and 3 point mutations in the CETP promoter were also identified. Collectively, these rare mutations were found only in the HALP group but not in the control group (8% vs 0%, p = 0.0056). One common variant of CETP (p.Asp459Gly) was found at a higher frequency in the HALP group (23% vs 4%, p = 0.000074). Altogether, rare variants of CETP or LIPC and/or the common CETP p.Asp459Gly variant were found in 30% of the HALP group and 4% of the controls (p = 0.0000014). No rare variant of LIPG was identified. In conclusion, common and rare genetic variants in CETP and LIPC, but not LIPG, were more commonly found in the Thai HALP group, which could potentially contribute to high high-density lipoprotein cholesterol phenotypes in this population.

Severe hypertriglyceridaemia as a result of familial chylomicronaemia: the Cape Town experience.

Lipoprotein lipase deficiency causes severe hypertriglyceridaemia due to chylomicronaemia, and leads to recurrent and potentially life-threatening pancreatitis. This disorder can only be managed by dietary fat restriction as drugs are ineffective. We review the experience with familial chylomicronaemia in patients who attended the lipid clinics at Groote Schuur Hospital and Red Cross Children's War Memorial Hospital in Cape Town. Criteria for inclusion were an initial plasma triglyceride concentration of >15 mmol/l and a typical type I Fredrickson hyperlipidaemia pattern on plasma lipoprotein electrophoresis. A total of 29 patients were seen over 25 years. The mean age of presentation was 10 years, but ranged from 0 to 43 years. The modes of presentation differed: pancreatitis (N=16), eruptive xanthomata (N=2), coincidental detection of hypertriglyceridaemia (N=2), screening relatives (N=7), and after death from pancreatitis (N=1). Plasma triglycerides responded rapidly and dramatically to dietary fat restriction, and some patients sustained good control of the hyperlipidaemia. The onset of pancreatitis was earlier in patients of Indian ancestry, suggesting a genotype/phenotype interaction within this disorder. Genetic work-up indicated founder effects in the Afrikaner and Indian patients. Lipaemic plasma should be taken seriously at all ages, and necessitates work-up at specialised clinics where the diagnosis of chylomicronaemia or type I hyperlipidaemia facilitates appropriate dietary management that can prevent pancreatitis.

Renin-angiotensin system polymorphisms and coronary events in familial hypercholesterolemia.

The role of renin-angiotensin system polymorphisms as risk factors for coronary heart disease (CHD) is controversial. This study investigated their role in patients with heterozygous familial hypercholesterolemia (FH). Polymorphism frequencies for angiotensin-I-converting enzyme insertion/deletion (ACE I/D), angiotensinogen M235T, and angiotensin-II type I receptor (AG2R) A1166C were determined in 112 patients with FH and 72 patients with polygenic hypercholesterolemia, of whom 26.7% and 41.6%, respectively, had established CHD. None of the polymorphisms were associated with risk of CHD in patients with polygenic hypercholesterolemia in this study. Logistic regression analysis of risk factors for CHD in patients with FH identified male sex (odds ratio [OR]=3.03; 95% CI, 3.07 to 3.72; P=0.05), smoking (OR=2.91; 95% CI, 2.16 to 4.24; P=0.05), diastolic blood pressure (OR=3.70; 95% CI, 3.43 to 3.97; P=0.02), plasma glucose (OR=3.31; 95% CI, 3. 10 to 3.52; P=0.04), and the AG2R A1166C polymorphism as risk factors. The OR for the AG2R A1166C polymorphism was 2.26 (95% CI, 1.26 to 3.72; P=0.06) and increased to 3.10 (95% CI, 1.20 to 7.52; P=0.04) after adjustment for other risk factors. The AG2R A1166C polymorphism may interact with severe hypercholesterolemia and other risk factors to increase risk of CHD in FH patients.

Ethnic variation and in vivo effects of the -93t-->g promoter variant in the lipoprotein lipase gene.

Recently, a (t-->g) transition at nucleotide -93 in the lipoprotein lipase (LPL) gene promoter has been observed in Caucasians. Here, we have compared the frequency of the -93g carriers in three distinct populations (Caucasians, South African Blacks, and Chinese). The carrier frequency in the Caucasian population was 1.7% (4/232), which was in contrast to the South African Black population, which had a frequency for this allele of 76.4% (123/161) of the individuals tested. This transition was not observed in the Chinese population under study. Near complete linkage disequilibrium between the -93g and the previously described D9N mutation was observed in the Caucasian population but not in South African Blacks. To further assess the ancestral origins of these DNA changes, DNA haplotyping using a CA repeat 5' to these substitutions was performed. The -93t allele was associated with only a few specific dinucleotide repeat sizes. In contrast, the -93g allele occurred on chromosomes with many different repeat lengths. The broad distribution of repeats on -93g carrying chromosomes, their high frequency in the South African Black population, and the conservation of the -93g allele among different species may suggest that the -93g allele is the ancestral allele on which a transition to t and the D9N mutations arose. The very high frequency of the -93g allele distinct from the N9 allele in a cohort of Black South Africans allowed us to specifically assess the phenotypic effects of the -93g allele on lipids. Individuals homozygous for the g allele at -93 showed mildly decreased triglycerides compared with individuals homozygous for the t allele (1.14 +/- 0.66 mmol/L versus 0.82 +/- 0.3; P = .04). Thus, the -93g allele in this cohort is associated with low plasma triglyceride levels.