Consensus document on diagnosis and management of familial hypercholesterolemia from the Italian Society for the Study of Atherosclerosis (SISA).

AIMS: Familial Hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism that causes an increased risk of premature atherosclerotic cardiovascular disease (ASCVD). Although early diagnosis and treatment of FH can significantly improve the cardiovascular prognosis, this disorder is underdiagnosed and undertreated. For these reasons the Italian Society for the Study of Atherosclerosis (SISA) assembled a Consensus Panel with the task to provide guidelines for FH diagnosis and treatment. DATA SYNTHESIS: Our guidelines include: i) an overview of the genetic complexity of FH and the role of candidate genes involved in LDL metabolism; ii) the prevalence of FH in the population; iii) the clinical criteria adopted for the diagnosis of FH; iv) the screening for ASCVD and the role of cardiovascular imaging techniques; v) the role of molecular diagnosis in establishing the genetic bases of the disorder; vi) the current therapeutic options in both heterozygous and homozygous FH. Treatment strategies and targets are currently based on low-density lipoprotein cholesterol (LDL-C) levels, as the prognosis of FH largely depends on the magnitude of LDL-C reduction achieved by lipid-lowering therapies. Statins with or without ezetimibe are the mainstay of treatment. Addition of novel medications like PCSK9 inhibitors, ANGPTL3 inhibitors or lomitapide in homozygous FH results in a further reduction of LDL-C levels. LDL apheresis is indicated in FH patients with inadequate response to cholesterol-lowering therapies. CONCLUSION: FH is a common, treatable genetic disorder and, although our understanding of this disease has improved, many challenges still remain with regard to its identification and management.

APOC-III: a Gatekeeper in Controlling Triglyceride Metabolism.

PURPOSE OF REVIEW: Apolipoprotein C-III (ApoC-III) is a widely known player in triglyceride metabolism, and it has been recently recognized as a polyhedric factor which may regulate several pathways beyond lipid metabolism by influencing cardiovascular, metabolic, and neurological disease risk. This review summarizes the different functions of ApoC-III and underlines the recent findings related to its multifaceted pathophysiological role. RECENT FINDINGS: The role of ApoC-III has been implicated in HDL metabolism and in the development of atherosclerosis, inflammation, and ER stress in endothelial cells. ApoC-III has been recently considered an important player in insulin resistance mechanisms, lipodystrophy, diabetic dyslipidemia, and postprandial hypertriglyceridemia (PPT). The emerging evidence of the involvement of ApoC-III in the in the pathogenesis of Alzheimer's disease open the way to further study if modification of ApoC-III level slows disease progression. Furthermore, ApoC-III is clearly linked to cardiovascular disease (CVD) risk, and progression of coronary artery disease (CAD) as well as the calcification of aortic valve and recent clinical trials has pointed out the inhibition of ApoC-III as a promising approach to manage hypertriglyceridemia and prevent CVD. Several evidences highlight the role of ApoC-III not only in triglyceride metabolism but also in several cardio-metabolic pathways. Results from recent clinical trials underline that the inhibition of ApoC-III is a promising therapeutical strategy for the management of severe hypertriglyceridemia and in CVD prevention.

Lifestyle versus ezetimibe plus lifestyle in patients with biopsy-proven non-alcoholic steatohepatitis (LISTEN): A double-blind randomised placebo-controlled trial.

BACKGROUND AND AIMS: The LISTEN trial (ClinicalTrial.gov accession: NCT01950884) is a phase IV 52 weeks double blind parallel randomized controlled trial that evaluated the effect of ezetimibe plus lifestyle and dietary intervention (eze) vs. lifestyle and dietary intervention alone (placebo) on progression and complications of non-alcoholic steatohepatitis (NASH) evaluated by liver histology. METHODS AND RESULTS: Forty patients with NASH ascertained by histology were randomly allocated on the two study groups and subjected to a follow-up of 52 weeks, when they underwent a second liver biopsy. Main composite end point (EP) was based on the histological improvement in the severity of NASH. Thirty patients completed the study, Eze treatment was not able to improve the primary EP in comparison with placebo, with and odds ratio of 1.029 (0.18-6.38), p = 0.974. Treatment emergent adverse events registered during the study were not more prevalent in the treatment arm. CONCLUSIONS: ezetimibe administered on top of lifestyle and dietary modification failed to improve the histology of NASH in comparison with lifestyle and dietary modification alone. TRIAL ACCESSION NUMBER: ClinicalTrial.gov: NCT01950884.

A subgroup analysis of the ODYSSEY APPRISE study: Safety and efficacy of alirocumab in the Italian cohort.

BACKGROUND AND AIMS: ODYSSEY APPRISE trial evaluated efficacy and safety of alirocumab in 994 patients with hypercholesterolemia and high CV risk in a real-life setting. The aim of the present report is to detail on the Italian cohort enrolled and treated in the trial. METHODS AND RESULTS: The methodology of the of the multinational, single-arm, Phase 3b open-label ODYSSEY APPRISE (Clinicaltrials.gov: NCT02476006) has been previously reported. 255 Italian patients were enrolled and treated according to the trial protocol. Overall mean exposure to alirocumab was 83.3 ± 27.7 weeks. At week 12, LDL-C decreased by 51.3 ± 23.1% and this reduction was overall maintained for the duration of the study. A similar reduction was observed in patients with and without heterozygous familial hypercholesterolemia (HeFH 50.7% ± 23.9 vs. non-FH, 53.6% ± 19.6). LDL-C was reduced below 1.8 mmol/L and/or by ≥ 50% reduction from baseline in 62% of patients overall (61% in HeFH and 67% in non-FH). Alirocumab was similarly well tolerated in the Italian cohort as in the entire study population and the more common treatment emergent adverse events (TEAEs) were influenza, myalgia and nasopharyngitis. The incidence LDL-C levels <25 mg/dl and <15 mg/dl, was 8.2% and 2.9% respectively. CONCLUSION: The efficacy and safety of alirocumab in a real-life setting, in the Italian subgroup of patients are consistent with findings in the entire study population and confirm that alirocumab is a beneficial approach to further reduce LDL-C levels in patients at high CV risk on maximally tolerated conventional lipid lowering treatment. GOV IDENTIFIER: NCT02476006.

rs629301 CELSR2 polymorphism confers a ten-year equivalent risk of critical stenosis assessed by coronary angiography.

BACKGROUND AND AIMS: Novel genetic determinants associated with coronary artery disease (CAD) have been discovered by genome wide association studies. Variants encompassing the CELSR2- PSRC1-SORT1 gene cluster have been associated with CAD. This study is aimed to investigate the rs629301 polymorphism association with the extent of CAD evaluated by coronary angiography (CAG), and to evaluate its associations with an extensive panel of lipid and lipoprotein measurements in a large Italian cohort of 2429 patients. METHODS AND RESULTS: The patients were collected by four Intensive Care Units located in Palermo and Verona (Italy). Clinical Records were filed, blood samples were collected, lipids and apolipoproteins (apo) were measured in separate laboratories. CAD was defined by the presence of stenotic arteries (>50% lumen diameter) by CAG. The presence of CAD was associated with the rs629301 genotype. Patients with CAD were 78% and 73% (p = 0.007) of the T/T vs. T/G + G/G genotype carriers respectively. T/T genotype was also correlated with the number of stenotic arteries, with a 1.29 (1.04-1.61) risk to have a three-arteries disease. T/T genotype correlated with higher levels of LDL-, non-HDL cholesterol, apoB, apoE and apoCIII, and lower HDL-cholesterol. Logistic Regression confirmed that rs629301was associated with CAD independently from the common risk factors, with a risk similar to that conferred by ten years of age [odds ratios were 1.43 (1.04-1.96) and 1.39 (1.22-1.58) respectively]. CONCLUSIONS: rs629301 risk allele was independently associated with the extension and severity of CAD and positively with apoE and apoB containing lipoproteins.

Lack of phenotypic additive effect of familial defective apolipoprotein B3531 in familial hypercholesterolaemia.

Familial defective apolipoprotein (apo) B (FDB) and familial hypercholesterolaemia (FH) are the two common genetic conditions that cause hypercholesterolaemia. R3531C mutation of the APOB gene is a rare cause of FDB. Individuals with both FDB and FH are rare. A 51-year-old man with hypercholesterolaemia (11.4 mmol/L) and his family were studied. Low-density lipoprotein (LDL) receptor (LDLR) and APOB genes were analysed by direct sequencing. LDL of four subjects were studied in a fibroblast LDL receptor-binding displacement assay. We found a mutation of the LDLR gene (p.Y398X) in the proband and in four other family members: the p.R3531C APOB gene mutation was also found in the proband, his father and his children. The proband and his son were thus compound heterozygotes for both FH and FDB. Double heterozygotes did not show higher cholesterol levels compared to carriers of LDLR gene mutation alone. LDL from one of the carriers of the p.R3531C alone exhibited a binding ability, which was similar to a normal subject. This is the first report in Italy of the p.R3531C mutation, and our results show that this mutation has no effect in LDLR p.Y398X/APOB p.R3531C double heterozygotes.

NPC1L1 and ABCG5/8 induction explain synergistic fecal cholesterol excretion in ob/ob mice co-treated with PPAR-α and LXR agonists.

Reverse cholesterol transport (RCT) and transintestinal cholesterol efflux (TICE) are two important pathways for body cholesterol elimination. We studied these pathways in an animal model of diabetes and obesity (ob/ob) where HDL function is compromised as a result of hyperglycemia, low-grade inflammation and oxidative stress. Co-treatment of ob/ob mice with PPAR-α (fenofibrate) and LXR (T0901317) agonists increased fecal cholesterol by 12-fold; PPAR-α and LXR agonists individually showed 2.6- and 4.0-fold fecal cholesterol excretion, respectively. We investigated the mechanism of synergistic efficacy of PPAR-α and LXR agonists in fecal cholesterol excretion. LXR agonist and the combination of PPAR-α and LXR agonists had greater HDL-C elevation. Ex vivo cholesterol efflux showed correlation with the fecal cholesterol excretion but was not sufficient to explain 12-fold increases in the fecal cholesterol in the co-treated mice. Therefore, we examined TICE to explain the 12-fold increases in the fecal cholesterol. A strong positive correlation of fecal cholesterol with ATP binding cassette transporter G5 (ABCG5) and G8 and a negative correlation with NPC1L1 was observed. ABCG5, G8 and NPC1L1 are involved in intestinal cholesterol absorption. The extent of influence of PPAR-α and LXR agonists on RCT and TICE was distinctly different. PPAR-α agonist increased fecal cholesterol primarily by influencing TICE, while LXR agonist influenced fecal cholesterol excretion via both RCT and TICE mechanisms. Synergistic efficacy on fecal cholesterol excretion following co-treatment with PPAR-α and LXR agonists occurred through a combination of RCT, TICE, and the key enzyme in bile synthesis, cholesterol 7-α hydroxylase (cyp7a1). These results suggest that cholesterol efflux, biliary cholesterol excretion, and TICE collectively contributed to the 12-fold increases in the fecal cholesterol excretion in ob/ob mice co-treated with PPAR-α and LXR agonists.

Characterization of a mutant form of human apolipoprotein B (Thr26_Tyr27del) associated with familial hypobetalipoproteinemia.

We have previously identified a deletion mutant of human apoB [apoB (Thr26_Tyr27del)] in a subject with primary hypobetalipoproteinemia. The present study determined the effect of Thr26_Tyr27del mutation on apoB secretion using transfected McA-RH7777 cells. Transient or stable transfection of apoB-48 containing the Thr26_Tyr27del mutation showed drastically reduced secretion of the mutant as compared to wild-type apoB-48. No lipoproteins containing the mutant apoB-48 were secreted into the medium. Incubation of transfected cells in a lipid-rich medium in the presence of cycloheximide showed rapid turnover of cell-associated mutant apoB-48 as compared to that of wild-type apoB-48. Immunofluorescence experiments showed that the mutant apoB-48 was mostly localized in the endoplasmic reticulum. Treatment with the proteasomal inhibitor MG132 markedly attenuated the turnover of cell-associated mutant apoB-48, whereas treatment with inhibitors of autophagosomal/lysosomal function (e.g. 3-MA or ammonium chloride) had no effect. Taken together, these results indicated that the defective secretion of the Thr26_Tyr27del mutant was associated with increased intracellular degradation of apoB through the proteasome-dependent pathway.

Proprotein Convertase Subtilisin Kexin Type 9 Inhibition for Autosomal Recessive Hypercholesterolemia-Brief Report.

OBJECTIVE: Proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors lower low-density lipoprotein (LDL) cholesterol in the vast majority of patients with autosomal dominant familial hypercholesterolemia. Will PCSK9 inhibition with monoclonal antibodies, in particular alirocumab, be of therapeutic value for patients with autosomal recessive hypercholesterolemia (ARH)? APPROACH AND RESULTS: Primary lymphocytes were obtained from 28 genetically characterized ARH patients and 11 controls. ARH lymphocytes treated with mevastatin were incubated with increasing doses of recombinant PCSK9 with or without saturating concentrations of alirocumab. Cell surface LDL receptor expression measured by flow cytometry and confocal microscopy was higher in ARH than in control lymphocytes. PCSK9 significantly reduced LDL receptor expression in ARH lymphocytes albeit to a lower extent than in control lymphocytes (25% versus 76%, respectively), an effect reversed by alirocumab. Fluorescent LDL cellular uptake, also measured by flow cytometry, was reduced in ARH lymphocytes compared with control lymphocytes. PCSK9 significantly lowered LDL cellular uptake in ARH lymphocytes, on average by 18%, compared with a 46% reduction observed in control lymphocytes, an effect also reversed by alirocumab. Overall, the effects of recombinant PCSK9, and hence of alirocumab, on LDL receptor expression and function were significantly less pronounced in ARH than in control cells. CONCLUSIONS: PCSK9 inhibition with alirocumab on top of statin treatment has the potential to lower LDL cholesterol in some autosomal recessive hypercholesterolemia patients.

Albumin versus solvent/detergent-treated pooled plasma as replacement fluid for long-term plasma exchange therapy in a patient with primary hypertriglyceridemia and recurrent hyperlipidemic pancreatitis.

BACKGROUND: Chylomicronemia syndrome is a metabolic condition characterized by severe fasting hypertrigliceridemia (≥ 1000 mg/dL) and other clinical features including chronic abdominal pain and recurrent acute pancreatitis. In patients with acute or recurrent pancreatitis, plasma exchange (PEx) is indicated for the treatment of acute disease and prevention of recurrence. The use of plasma instead of albumin as replacement fluid has been suggested for its putative ability to replace the deficient enzyme possibly leading to better clinical improvement. CASE REPORT: A 40-year-old man with chylomicronemia syndrome due to a newly identified loss-of-function mutation in the lipoprotein lipase (LPL) gene (IVS2, c.250-1G/C) has been treated at our hospital since the age of 13. From age 18 to age 34, the patient had five episodes of acute pancreatitis while his triglyceride (TG) levels were extremely high (2500-4000 mg/dL). As the TG levels remained stable over 4000 mg/dL despite the maximum medical treatment, the patient started long-term PEx treatment on a weekly basIs. Both albumin and plasma have been used as replacement solution. Thirty months from the beginning of this treatment, no episode of acute pancreatitis has been reported, and the chronic abdominal pain fully disappeared. No differences were observed between the use of albumin or plasma as replacement solution. CONCLUSION: Long-term PEx is effective in preventing the recurrence of acute pancreatitis and in treatment of chronic abdominal pain in this patient with chylomicronemia syndrome. Plasma is not more effective than albumin in lipid reduction, likely because of its extremely low enzyme content. Therefore, in patients with LPL deficiency serum albumin should be preferred to plasma as replacement fluid because of the low rate of side effects and reduced costs.

Novel CREB3L3 Nonsense Mutation in a Family With Dominant Hypertriglyceridemia.

OBJECTIVE: Cyclic AMP responsive element-binding protein 3-like 3 (CREB3L3) is a novel candidate gene for dominant hypertriglyceridemia. To date, only 4 kindred with dominant hypertriglyceridemia have been found to be carriers of 2 nonsense mutations in CREB3L3 gene (245fs and W46X). We investigated a family in which hypertriglyceridemia displayed an autosomal dominant pattern of inheritance. APPROACH AND RESULTS: The proband was a 49-year-old woman with high plasma triglycerides (≤1300 mg/dL; 14.68 mmol/L). Her father had a history of moderate hypertriglyceridemia, and her 51-year-old brother had triglycerides levels as high as 1600 mg/dL (18.06 mmol/L). To identify the causal mutation in this family, we analyzed the candidate genes of recessive and dominant forms of primary hypertriglyceridemia by direct sequencing. The sequencing of CREB3L3 gene led to the discovery of a novel minute frame shift mutation in exon 3 of CREB3L3 gene, predicted to result in the formation of a truncated protein devoid of function (c.359delG-p.K120fsX20). Heterozygosity for the c.359delG mutation resulted in a severe phenotype occurring later in life in the proband and her brother and a good response to diet and a hypotriglyceridemic treatment. The same mutation was detected in a 13-year-old daughter who to date is normotriglyceridemic. CONCLUSIONS: We have identified a novel pathogenic mutation in CREB3L3 gene in a family with dominant hypertriglyceridemia with a variable pattern of penetrance.

FragClust and TestClust, two informatics tools for chemical structure hierarchical clustering analysis applied to lipidomics. The example of Alzheimer's disease.

Lipidomic analysis is able to measure simultaneously thousands of compounds belonging to a few lipid classes. In each lipid class, compounds differ only by the acyl radical, ranging between C10:0 (capric acid) and C24:0 (lignoceric acid). Although some metabolites have a peculiar pathological role, more often compounds belonging to a single lipid class exert the same biological effect. Here, we present a lipidomics workflow that extracts the tandem mass spectrometry data from individual files and uses them to group compounds into structurally homogeneous clusters by chemical structure hierarchical clustering analysis (CHCA). The case-to-control peak area ratios of the metabolites are then analyzed within clusters. We created two freely available applications to assist the workflow: FragClust to generate the tables to be subjected to CHCA, and TestClust to perform statistical analysis on clustered data. We used the lipidomics data from the plasma of Alzheimer's disease (AD) patients in comparison with healthy controls to test the workflow. To date, the search for plasma biomarkers in AD has not provided reliable results. This article shows that the workflow is helpful to understand the behavior of whole lipid classes in plasma of AD patients.

Beyond statins: new lipid lowering strategies to reduce cardiovascular risk.

Statins are the first-line therapy in LDL-Cholesterol (LDL-C) reduction and its clinical use has contributed to significant prevention and treatment of atherosclerotic vascular disease. Yet, a significant proportion of patients remain at high risk. Recently, a number of new therapies have been developed to further lower LDL-C. These agents may provide clinical benefit on top of statin therapy in patients with high residual risk, severe hypercholesterolemia or as an alternative for patients who are intolerant to statins. We review four novel approaches based on the inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9), apolipoprotein-B100 (apoB), Cholesteryl ester transport protein (CETP) and microsomal triglyceride transfer protein (MTP). ApoB and MTP inhibitors (Mipomersen and Lomitapide) are indicated only for homozygous familial hypercholesterolemia patients. The results of ongoing trials with CETP and PCSK9 inhibitors may warrant a wider employment in different categories of patients at high risk for cardiovascular disease.

A novel APOB mutation identified by exome sequencing cosegregates with steatosis, liver cancer, and hypocholesterolemia.

OBJECTIVE: In familial hypobetalipoproteinemia, fatty liver is a characteristic feature, and there are several reports of associated cirrhosis and hepatocarcinoma. We investigated a large kindred in which low-density lipoprotein cholesterol, fatty liver, and hepatocarcinoma displayed an autosomal dominant pattern of inheritance. APPROACH AND RESULTS: The proband was a 25-year-old female with low plasma cholesterol and hepatic steatosis. Low plasma levels of total cholesterol and fatty liver were observed in 10 more family members; 1 member was affected by liver cirrhosis, and 4 more subjects died of either hepatocarcinoma or carcinoma on cirrhosis. To identify the causal mutation in this family, we performed exome sequencing in 2 participants with hypocholesterolemia and fatty liver. Approximately 22 400 single nucleotide variants were identified in each sample. After variant filtering, 300 novel shared variants remained. A nonsense variant, p.K2240X, attributable to an A>T mutation in exon 26 of APOB (c.6718A>T) was identified, and this variant was confirmed by Sanger sequencing. The gentotypic analysis of 16 family members in total showed that this mutation segregated with the low cholesterol trait. In addition, genotyping of the PNPLA3 p.I148M did not show significant frequency differences between carriers and noncarriers of the c.6718A>T APOB gene mutation. CONCLUSIONS: We used exome sequencing to discover a novel nonsense mutation in exon 26 of APOB (p.K2240X) responsible for low cholesterol and fatty liver in a large kindred. This mutation may also be responsible for cirrhosis and liver cancer in this family.

Erdheim-Chester disease as complex clinical presentation and diagnosis: A case report and concise review of literature.

RATIONALE: Erdheim-Chester disease (ECD) is a rare multisystemic disease characterized by the infiltration of multiple organs by foamy CD68 + CD1a-histiocytes. The genetic background consists of gain-of-function somatic mutations in the mitogen-activated protein kinase pathway. The purpose of the present paper is to make a contribution to the scientific literature on ECD by reporting our experience with a complex clinical case report, along with a concise review of the literature. We discussed the unusual clinical presentation, the complex diagnostic process and the comparison with other published cases. PATIENT CONCERNS: A 70-year-old man presented with arthralgia due to multiple bone areas of sclerosis, first diagnosed with metastases of a prostatic neoplasm. Sequential thorax-abdomen, femoral and homer contrast-enhanced computed tomography (CT) showed pericardial effusion, pulmonary fibrosis, and perirenal fibrous tissue as "hairy kidneys." He underwent. Three bone biopsies were unsuccessful to reach diagnosis. DIAGNOSES: A xanthelasma biopsy showed histopathological signs compatible with ECD; genetic analysis showed the mutation BRAFV600E. INTERVENTIONS: The patient underwent targeted therapy with vemurafenib (BRAF-inhibitor), discontinued 2 weeks later due to the onset of a diffuse erythematous papular rash on the trunk and limbs. OUTCOMES: At the 1-year follow-up, there was only progression of chronic kidney disease (CKD). LESSONS: The present case report describes how ECD diagnosis could represent a challenge for clinicians, owing to its heterogeneous clinical presentation. Early diagnosis followed by prompt therapy is essential for modifying the natural history of the disease.

Clinical characteristics and plasma lipids in subjects with familial combined hypolipidemia: a pooled analysis.

Angiopoietin-like 3 (ANGPTL3) regulates lipoprotein metabolism by modulating extracellular lipases. Loss-of function mutations in ANGPTL3 gene cause familial combined hypolipidemia (FHBL2). The mode of inheritance and hepatic and vascular consequences of FHBL2 have not been fully elucidated. To get further insights on these aspects, we reevaluated the clinical and the biochemical characteristics of all reported cases of FHBL2. One hundred fifteen FHBL2 individuals carrying 13 different mutations in the ANGPTL3 gene (14 homozygotes, 8 compound heterozygotes, and 93 heterozygotes) and 402 controls were considered. Carriers of two mutant alleles had undetectable plasma levels of ANGPTL3 protein, whereas heterozygotes showed a reduction ranging from 34% to 88%, according to genotype. Compared with controls, homozygotes as well as heterozygotes showed a significant reduction of all plasma lipoproteins, while no difference in lipoprotein(a) [Lp(a)] levels was detected between groups. The prevalence of fatty liver was not different in FHBL2 subjects compared with controls. Notably, diabetes mellitus and cardiovascular disease were absent among homozygotes. FHBL2 trait is inherited in a codominant manner, and the lipid-lowering effect of two ANGPTL3 mutant alleles was more than four times larger than that of one mutant allele. No changes in Lp(a) were detected in FHBL2. Furthermore, our analysis confirmed that FHBL2 is not associated with adverse clinical sequelae. The possibility that FHBL2 confers lower risk of diabetes and cardiovascular disease warrants more detailed investigation.

Prevalence of ANGPTL3 and APOB gene mutations in subjects with combined hypolipidemia.

OBJECTIVE: Mutations of the ANGPTL3 gene have been associated with a novel form of primary hypobetalipoproteinemia, the combined hypolipidemia (cHLP), characterized by low total cholesterol and low HDL-cholesterol levels. The aim of this work is to define the role of ANGPTL3 gene as determinant of the combined hypolipidemia phenotype in 2 large cohorts of 913 among American and Italian subjects with primary hypobetalipoproteinemia (total cholesterol<5th percentile). METHODS AND RESULTS: The combined hypolipidemia cut-offs were chosen according to total cholesterol and HDL-cholesterol levels reported in the ANGPTL3 kindred described to date: total cholesterol levels, <2nd percentile and HDL-cholesterol, levels<2nd decile. Seventy-eight subjects with combined hypolipidemia were analyzed for ANGPTL3 and APOB genes. We identified nonsense and/or missense mutations in ANGPTL3 gene in 8 subjects; no mutations of the APOB gene were found. Mutated ANGPTL3 homozygous/compound heterozygous subjects showed a more severe biochemical phenotype compared to heterozygous or ANGPTL3 negative subjects, although ANGPTL3 heterozygotes did not differ from ANGPTL3 negative subjects. CONCLUSION: These results demonstrated that in a cohort of subjects with severe primary hypobetalipoproteinemia the prevalence of ANGPTL3 gene mutations responsible for a combined hypolipidemia phenotype is about 10%, whereas mutations of APOB gene are absent.

Prothrombotic gene variants as risk factors of acute myocardial infarction in young women.

BACKGROUND: Acute myocardial infarction (AMI) in young women represent an extreme phenotype associated with a higher mortality compared with similarly aged men. Prothrombotic gene variants could play a role as risk factors for AMI at young age. METHODS: We studied Factor V Leiden, FII G20210A, MTHFR C677T and beta-fibrinogen -455G>A variants by real-time PCR in 955 young AMI (362 females) and in 698 AMI (245 females) patients. The data were compared to those obtained in 909 unrelated subjects (458 females) from the general population of the same geographical area (southern Italy). RESULTS: In young AMI females, the allelic frequency of either FV Leiden and of FII G20210A was significantly higher versus the general population (O.R.: 3.67 for FV Leiden and O.R.: 3.84 for FII G20210A; p<0.001). Among AMI patients we showed only in males that the allelic frequency of the MTHFR C677T variant was significantly higher as compared to the general population. Such difference was due to a significantly higher frequency in AMI males of the MTHFR C677T variant homozygous genotype (O.R. 3.05). DISCUSSION AND CONCLUSION: Our data confirm that young AMI in females is a peculiar phenotype with specific risk factors as the increased plasma procoagulant activity of FV and FII. On the contrary, the homozygous state for the 677T MTHFR variant may cause increased levels of homocysteine and/or an altered folate status and thus an increased risk for AMI, particularly in males. The knowledge of such risk factors (that may be easily identified by molecular analysis) may help to improve prevention strategies for acute coronary diseases in specific risk-group subjects.