Treatment of pediatric heterozygous familial hypercholesterolemia 7 years after the EAS recommendations: Real-world results from a large French cohort.

BACKGROUND: Heterozygous familial hypercholesterolemia (HeFH) predisposes to premature cardiovascular diseases. Since 2015, the European Atherosclerosis Society has advocated initiation of statins at 8-10 years of age and a low-density lipoprotein cholesterol (LDL-C) target of <135 mg/dL. Longitudinal data from large databases on pharmacological management of pediatric HeFH are lacking. OBJECTIVE: Here, we describe treatment patterns and LDL-C goal attainment in pediatric HeFH using longitudinal real-world data. METHODS: This was a retrospective and prospective multicenter cohort study (2015-2021) of children with HeFH, diagnosed genetically or clinically, aged <18 years, and followed up in the National French Registry of FH (REFERCHOL). Data on the study population as well as treatment patterns and outcomes are summarized as mean±SD. RESULTS: We analyzed the data of 674 HeFH children (age at last visit: 13.1 ± 3.6 years; 82.0 % ≥10 years; 52.5 % females) who were followed up for a mean of 2.8 ± 3.5 years. Initiation of lipid-lowering therapy was on average at 11.8 ± 3.0 years of age for a duration of 2.5 ± 2.8 years. At the last visit, among patients eligible for treatment (573), 36 % were not treated, 57.1 % received statins alone, 6.4 % statins with ezetimibe, and 0.2 % ezetimibe alone. LDL-C was 266±51 mg/dL before treatment and 147±54 mg/dL at the last visit (-44.7 %) in treated patients. Regarding statins, 3.3 %, 65.1 %, and 31.6 % of patients received high-, moderate-, and low-intensity statins, respectively. Overall, 59 % of children on statin therapy alone and 35.1 % on bitherapy did not achieve the LDL-C goal; fewer patients in the older age group did not reach the treatment goal. CONCLUSION: Pediatric patients with FH followed up in specialist lipid clinics in France receive late treatment, undertreatment, or suboptimal treatment and half of them do not reach the therapeutic LDL-C goal. Finding a more efficient framework for linking scientific evidence to clinical practice is needed.

Effect of causative genetic variants on atherosclerotic cardiovascular disease in heterozygous familial hypercholesterolemia patients.

Background: Heterozygous familial hypercholesterolemia (HFH) is an autosomal dominant genetic disorder leading to a lifetime exposure to high low-density lipoprotein cholesterol (LDL-c) level and an increased risk of premature atherosclerotic cardiovascular disease (ASCVD). We evaluate the effect of a causative genetic variant to predict ASCVD in HFH patients undergoing treatment. Materials and methods: A retrospective cohort was conducted on 289 patients with possible, probable, and definite diagnosis of HFH according to Dutch Lipid Clinic Network Score and in whom DNA analyses were performed and mean LDL-c level was above 155 mg/dl. The study population was divided into groups based on the presence or not of a causative variant (pathogenic or likely pathogenic). We observed each of the study's participants for the occurrence of ASCVD. Results: A causative variant was detected in 42.2% of study participants, and ASCVD has occurred in 21.5% of HFH patients. The incidence of ASCVD (27% vs. 17.4%, p = 0.048) and the mean of LDL-c under an optimal medical treatment (226 ± 59 mg/dl vs. 203 ± 37 mg/dl, p = 0.001) were higher in HFH-causative variant carriers than others. After adjusting on confounders, ASCVD was positively associated with LDL-c level [OR = 2.347; 95% (1.305-4.221), p = 0.004] and tends toward a negative association with HDL-c level [OR = 0.140; 95% (0.017-1.166), p = 0.059]. There is no more association between the detection of a causative variant and the occurrence of ASCVD [OR = 1.708; 95% (0.899-3.242), p = 0.102]. Kaplan Meier and log rank test showed no significant differences in event-free survival analysis between study groups (p = 0.523). Conclusion: In this study population under medical care, it seems that the presence of a causative variant did not represent an independent predictor of adverse cardiovascular outcomes in HFH patients, and LDL-c level played an undisputable causal role.

Additive Effect of APOE Rare Variants on the Phenotype of Familial Hypercholesterolemia.

BACKGROUND: Autosomal dominant hypercholesterolemia (ADH) is due to deleterious variants in LDLR, APOB, or PCSK9 genes. Double heterozygote for these genes induces a more severe phenotype. More recently, a new causative variant of heterozygous ADH was identified in APOE. Here we study the phenotype of 21 adult patients, double heterozygotes for rare LDLR and rare APOE variants (LDLR+APOE) in a national wide French cohort. METHODS: LDLR, APOB, PCSK9, and APOE genes were sequenced in 5743 probands addressed for ADH genotyping. The lipid profile and occurrence of premature atherosclerotic cardiovascular diseases were compared between the LDLR+APOE carriers (n=21) and the carriers of the same LDLR causative variants alone (n=22). RESULTS: The prevalence of LDLR+APOE carriers in this French ADH cohort is 0.4%. Overall, LDL (low-density lipoprotein)-cholesterol concentrations were 23% higher in LDLR+APOE patients than in LDLR patients (9.14±2.51 versus 7.43±1.59 mmol/L, P=0.0221). When only deleterious or probably deleterious variants were considered, the LDL-cholesterol concentrations were 46% higher in LDLR+APOE carriers than in LDLR carriers (10.83±3.45 versus 7.43±1.59 mmol/L, P=0.0270). Two patients exhibited a homozygous familial hypercholesterolemia phenotype (LDL-cholesterol >13 mmol/L). Premature atherosclerotic cardiovascular disease was more common in LDLR+APOE patients than in LDLR carriers (70% versus 30%, P=0.026). CONCLUSIONS: Although an incomplete penetrance should be taken into account for APOE variant classification, these results suggest an additive effect of deleterious APOE variants on ADH phenotype highlighting the relevance of APOE sequencing.

APOE Molecular Spectrum in a French Cohort with Primary Dyslipidemia.

Primary hypercholesterolemia is characterized by elevated LDL-cholesterol (LDL-C) levels isolated in autosomal dominant hypercholesterolemia (ADH) or associated with elevated triglyceride levels in familial combined hyperlipidemia (FCHL). Rare APOE variants are known in ADH and FCHL. We explored the APOE molecular spectrum in a French ADH/FCHL cohort of 5743 unrelated probands. The sequencing of LDLR, PCSK9, APOB, and APOE revealed 76 carriers of a rare APOE variant, with no mutation in LDLR, PCSK9, or APOB. Among the 31 APOE variants identified here, 15 are described in ADH, 10 in FCHL, and 6 in both probands. Five were previously reported with dyslipidemia and 26 are novel, including 12 missense, 5 synonymous, 2 intronic, and 7 variants in regulatory regions. Sixteen variants were predicted as pathogenic or likely pathogenic, and their carriers had significantly lower polygenic risk scores (wPRS) than carriers of predicted benign variants. We observed no correlation between LDL-C levels and wPRS, suggesting a major effect of APOE variants. Carriers of p.Leu167del were associated with a severe phenotype. The analysis of 11 probands suggests that carriers of an APOE variant respond better to statins than carriers of a LDLR mutation. Altogether, we show that the APOE variants account for a significant contribution to ADH and FCHL.

Whole Exome/Genome Sequencing Joint Analysis of a Family with Oligogenic Familial Hypercholesterolemia.

Autosomal Dominant Hypercholesterolemia (ADH) is a genetic disorder caused by pathogenic variants in LDLR, APOB, PCSK9 and APOE genes. We sought to identify new candidate genes responsible for the ADH phenotype in patients without pathogenic variants in the known ADH-causing genes by focusing on a French family with affected and non-affected members who presented a high ADH polygenic risk score (wPRS). Linkage analysis, whole exome and whole genome sequencing resulted in the identification of variants p.(Pro398Ala) in CYP7A1, p.(Val1382Phe) in LRP6 and p.(Ser202His) in LDLRAP1. A total of 6 other variants were identified in 6 of 160 unrelated ADH probands: p.(Ala13Val) and p.(Aps347Asn) in CYP7A1; p.(Tyr972Cys), p.(Thr1479Ile) and p.(Ser1612Phe) in LRP6; and p.(Ser202LeufsTer19) in LDLRAP1. All six probands presented a moderate wPRS. Serum analyses of carriers of the p.(Pro398Ala) variant in CYP7A1 showed no differences in the synthesis of bile acids compared to the serums of non-carriers. Functional studies of the four LRP6 mutants in HEK293T cells resulted in contradictory results excluding a major effect of each variant alone. Within the family, none of the heterozygous for only the LDLRAP1 p.(Ser202His) variant presented ADH. Altogether, each variant individually does not result in elevated LDL-C; however, the oligogenic combination of two or three variants reveals the ADH phenotype.

Prevalence of familial hypercholesterolaemia in patients presenting with premature acute coronary syndrome.

BACKGROUND: Familial hypercholesterolaemia (FH) is responsible for severe hypercholesterolaemia and premature cardiovascular morbidity and mortality. The first clinical event is typically an acute coronary syndrome. Unfortunately, FH is largely underdiagnosed in the general population. AIMS: To assess the prevalence of clinical FH among patients with premature (aged≤50 years) acute myocardial infarction (MI) and compare it with FH prevalence in a control population. METHODS: We reviewed in our database all patients with premature MI (aged≤50 years) referred to Ambroise Paré Hospital from 2014 to 2018. FH prevalence was estimated via the Dutch Lipid Clinic Network score, based on personal and family history of premature cardiovascular disease and low-density lipoprotein cholesterol concentrations. FH was "possible" with a score between 3 and 5 points, "probable" with a score between 6 and 8 and "definite" with a score above 8. FH prevalence in young patients with MI was then compared with FH prevalence in a general population of the same age from the CARVAR 92 prospective cohort. RESULTS: Of the 457 patients with premature MI, 29 (6%) had "probable" or "definite" FH. In the CARVAR 92 cohort, 16 (0.16%) of 9900 subjects aged≤50 years had "probable" or "definite" FH. FH prevalence was 39 times greater among patients with premature MI than in the control population (P<0.0001). In multivariable analysis, FH was strongly associated with MI (adjusted odds ratio 38.4, 95% confidence interval 19.1-79.4). CONCLUSIONS: FH is>30-fold more common in patients referred for premature MI than in the general population; this highlights the need for FH screening after a first MI to enhance lipid-lowering therapy and allow early identification of family members.

Posttranscriptional Regulation of the Human LDL Receptor by the U2-Spliceosome.

BACKGROUND: The LDLR (low-density lipoprotein receptor) in the liver is the major determinant of LDL-cholesterol levels in human plasma. The discovery of genes that regulate the activity of LDLR helps to identify pathomechanisms of hypercholesterolemia and novel therapeutic targets against atherosclerotic cardiovascular disease. METHODS: We performed a genome-wide RNA interference screen for genes limiting the uptake of fluorescent LDL into Huh-7 hepatocarcinoma cells. Top hit genes were validated by in vitro experiments as well as analyses of data sets on gene expression and variants in human populations. RESULTS: The knockdown of 54 genes significantly inhibited LDL uptake. Fifteen of them encode for components or interactors of the U2-spliceosome. Knocking down any one of 11 out of 15 genes resulted in the selective retention of intron 3 of LDLR. The translated LDLR fragment lacks 88% of the full length LDLR and is detectable neither in nontransfected cells nor in human plasma. The hepatic expression of the intron 3 retention transcript is increased in nonalcoholic fatty liver disease as well as after bariatric surgery. Its expression in blood cells correlates with LDL-cholesterol and age. Single nucleotide polymorphisms and 3 rare variants of one spliceosome gene, RBM25, are associated with LDL-cholesterol in the population and familial hypercholesterolemia, respectively. Compared with overexpression of wild-type RBM25, overexpression of the 3 rare RBM25 mutants in Huh-7 cells led to lower LDL uptake. CONCLUSIONS: We identified a novel mechanism of posttranscriptional regulation of LDLR activity in humans and associations of genetic variants of RBM25 with LDL-cholesterol levels.

Challenging the traditional approach for interpreting genetic variants: Lessons from Fabry disease.

Fabry disease (FD) is an X-linked genetic disease due to pathogenic variants in GLA. The phenotype varies depending on the GLA variant, alpha-galactosidase residual activity, patient's age and gender and, for females, X chromosome inactivation. Over 1000 variants have been identified, many through screening protocols more susceptible to disclose non-pathogenic variants or variants of unknown significance (VUS). This, together with the non-specificity of some FD symptoms, challenges physicians attempting to interpret GLA variants. The traditional way to interpreting pathogenicity is based on a combined approach using allele frequencies, genomic databases, global and disease-specific clinical databases, and in silico tools proposed by the American College of Medical Genetics and Genomics. Here, a panel of FD specialists convened to study how expertise may compare with the traditional approach. Several GLA VUS, highly controversial in the literature (p.Ser126Gly, p.Ala143Thr, p.Asp313Tyr), were re-analyzed through reviews of patients' charts. The same was done for pathogenic GLA variants with some specificities. Our data suggest that input of geneticists and physicians with wide expertise in disease phenotypes, prevalence, inheritance, biomarkers, alleles frequencies, disease-specific databases, and literature greatly contribute to a more accurate interpretation of the pathogenicity of variants, bringing a significant additional value over the traditional approach.

Identification of a Variant in APOB Gene as a Major Cause of Hypobetalipoproteinemia in Lebanese Families.

Familial hypobetalipoproteinemia (FHBL) is a codominant genetic disorder characterized by reduced plasma levels of low-density lipoprotein cholesterol and apolipoprotein B. To our knowledge, no study on FHBL in Lebanon and the Middle East region has been reported. Therefore, we conducted genetic studies in unrelated families and probands of Lebanese origin presenting with FHBL, in order to identify the causes of this disease. We found that 71% of the recruited probands and their affected relatives were heterozygous for the p.(Arg490Trp) variant in the APOB gene. Haplotype analysis showed that these patients presented the same mutant haplotype. Moreover, there was a decrease in plasma levels of PCSK9 in affected individuals compared to the non-affected and a significant positive correlation between circulating PCSK9 and ApoB levels in all studied probands and their family members. Some of the p.(Arg490Trp) carriers suffered from diabetes, hepatic steatosis or neurological problems. In conclusion, the p.(Arg490Trp) pathogenic variant seems a cause of FHBL in patients from Lebanese origin, accounting for approximately 70% of the probands with FHBL presumably as a result of a founder mutation in Lebanon. This study is crucial to guide the early diagnosis, management and prevention of the associated complications of this disease.

APOE gene variants in primary dyslipidemia.

Apolipoprotein E (apoE) is a major apolipoprotein involved in lipoprotein metabolism. It is a polymorphic protein and different isoforms are associated with variations in lipid and lipoprotein levels and thus cardiovascular risk. The isoform apoE4 is associated with an increase in LDL-cholesterol levels and thus a higher cardiovascular risk compared to apoE3. Whereas, apoE2 is associated with a mild decrease in LDL-cholesterol levels. In the presence of other risk factors, apoE2 homozygotes could develop type III hyperlipoproteinemia (familial dysbetalipoproteinemia or FD), an atherogenic disorder characterized by an accumulation of remnants of triglyceride-rich lipoproteins. Several rare APOE gene variants were reported in different types of dyslipidemias including FD, familial combined hyperlipidemia (FCH), lipoprotein glomerulopathy and bona fide autosomal dominant hypercholesterolemia (ADH). ADH is characterized by elevated LDL-cholesterol levels leading to coronary heart disease, and due to molecular alterations in three main genes: LDLR, APOB and PCSK9. The identification of the APOE-p.Leu167del variant as the causative molecular element in two different ADH families, paved the way to considering APOE as a candidate gene for ADH. Due to non mendelian interacting factors, common genetic and environmental factors and perhaps epigenetics, clinical presentation of lipid disorders associated with APOE variants often strongly overlap. More studies are needed to determine the spectrum of APOE implication in each of the diseases, notably ADH, in order to improve clinical and genetic diagnosis, prognosis and patient management. The purpose of this review is to comment on these APOE variants and on the molecular and clinical overlaps between dyslipidemias.

Real-World Efficacy of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors (PCSK9i) in Heterozygous Familial Hypercholesterolemia Patients Referred for Lipoprotein Apheresis.

BACKGROUND A small proportion of familial hypercholesterolemia (FH) patients can adequately control this condition, although achieving the recommended targets for low-density lipoprotein cholesterol (LDL-c) levels remains a challenge. Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are new and potent lipid-lowering drugs. However, there is scarce literature on real-world data about their use in patients with FH. MATERIAL AND METHODS We examined the reduction in LDL-c levels from the baseline, after PCSK9i initiation in heterozygous familial hypercholesterolemia patients referred for lipoprotein apheresis in our regional lipid clinic. The study was conducted from March 2018 to September 2019, the period immediately after PCSK9i reimbursement was available in France. PCSK9i was added on top of the patients' maximal tolerated lipid-lowering regimens. RESULTS The study had 123 patients with heterozygous FH. The mean age of the patients was 59±11 years. The mean baseline LDL-c for all the participants was 277±78 mg/dl. It was 283±81 mg/dl in the PCSK9i monotherapy group (n=83), 247±68 mg/dl in the PCSK9i plus ezetimibe group (n=12), and 264±78 mg/dl in the PCSK9i plus statin and ezetimibe group (n=28). The mean decrease observed in the LDL-c level from baseline was 136±70 mg/dl (n=123), 125±60 mg/dl (n=83), 103±77 mg/dl (n=12), and 175±70 mg/dl (n=28), respectively. CONCLUSIONS An overall reduction of 49.1% from the baseline LDL-c was observed in the heterozygous FH population after PCSK9i initiation in a real-world experience. The group treated with PCSK9i ezetimibe plus statin showed further reduction of their LDL-c levels with a better responder rate, achieving the target 50% reduction in LDL-c from the baseline.

A Simple RFLP-Based Method for HFE Gene Multiplex Amplification and Determination of Hereditary Hemochromatosis-Causing Mutation C282Y and H63D Variant with Highly Sensitive Determination of Contamination.

Hereditary hemochromatosis is an autosomal recessive disorder with incomplete penetrance that results from excess iron absorption and can lead to chronic liver disease, fibrosis, cirrhosis, and hepatocellular carcinoma. The most common form of hereditary hemochromatosis in Western Europe is due to a homozygous mutation (p.(Cys282Tyr) or C282Y), in the HFE gene which encodes hereditary haemochromatosis protein. In the general European population, the frequency of the homozygous genotype is 0.4%, and this mutation explains up to 95% of hereditary hemochromatosis in France. We report here an improved PCR and restriction endonuclease assay based on multiplex amplification of HFE exon 4 (for C282Y detection), HFE exon 2 (for H63D detection), FZD1 gene (for digestion controls), and two Short Tandem Repeats (SE33 and FGA) for identity monitoring and contamination tracking. Fluorescent primers allow capillary electrophoresis, accurate allele tagging, and sensitive contamination detection.

Postprandial lipid absorption in seven heterozygous carriers of deleterious variants of MTTP in two abetalipoproteinemic families.

BACKGROUND: Abetalipoproteinemia, a recessive disease resulting from deleterious variants in MTTP (microsomal triglyceride transfer protein), is characterized by undetectable concentrations of apolipoprotein B, extremely low levels of low-density lipoprotein cholesterol in the plasma, and a total inability to export apolipoprotein B-containing lipoproteins from both the intestine and the liver. OBJECTIVE: To study lipid absorption after a fat load and liver function in 7 heterozygous relatives from 2 abetalipoproteinemic families, 1 previously unreported. RESULTS: Both patients are compound heterozygotes for p.(Arg540His) and either c.708_709del p.(His236Glnfs*11) or c.1344+3_1344+6del on the MTTP gene. The previously undescribed patient has been followed for 22 years with ultrastructure analyses of both the intestine and the liver. In these 2 families, 5 relatives were heterozygous for p.(Arg540His), 1 for p.(His236Glnfs*11) and 1 for c.1344+3_1344+6del. In 4 heterozygous relatives, the lipid absorption was normal independent of the MTTP variant. In contrast, in 3 of them, the increase in triglyceride levels after fat load was abnormal. These subjects were additionally heterozygous carriers of Asp2213 APOB in-frame deletion, near the cytidine mRNA editing site, which is essential for intestinal apoB48 production. Liver function appeared to be normal in all the heterozygotes except for one who exhibited liver steatosis for unexplained reasons. CONCLUSION: Our study suggests that a single copy of the MTTP gene may be sufficient for human normal lipid absorption, except when associated with an additional APOB gene alteration. The hepatic steatosis reported in 1 patient emphasizes the need for liver function tests in all heterozygotes until the level of risk is established.

Identification of the first Tangier disease patient in Lebanon carrying a new pathogenic variant in ABCA1.

BACKGROUND: The Middle East region is characterized by low levels of high-density lipoprotein cholesterol (HDL-C). To date, no genetic study has investigated the cause of low HDL-C in the Lebanese population. OBJECTIVE: Our objective was to study the genetic causes for hypoalphalipoproteinemia in a Lebanese family with extremely low HDL-C levels. METHODS: We sequenced the ABCA1 gene and evaluated cholesterol efflux, inflammatory, and metabolic profiles in the proband and his family. RESULTS: We identified the first Lebanese pathogenic variant in ABCA1 gene causing Tangier disease in a consanguineous family. The proband carried a novel homozygous pathogenic variant p.Gly592Asp in exon 14 of ABCA1, which segregated with the disease in the family. Functional study of the p.Gly592Asp pathogenic variant revealed that lipid-free apolipoprotein A-I-dependent cholesterol efflux was completely abolished in cholesterol-loaded human monocytes-derived macrophages isolated from the proband when compared to controls. Systemic inflammatory and metabolic assessments showed that plasma cytokines (MCP-1, MIP-1α, IL-6, CRP, TNF-α), adhesion molecules (ICAM-1, VCAM-1, E-selectin), inflammatory soluble receptors (sIL-6r, sTNFRI, sTNFRII), and metabolic markers (Insulin, C-peptide) were elevated in the proband when compared to controls. Noninvasive cardiovascular investigation revealed the presence of premature artery lesions in the proband. CONCLUSIONS: It is the first case of Tangier disease reported in Lebanon harboring a novel pathogenic variant in ABCA1. Further genetic research is needed in the Middle East where the consanguinity rate is elevated, to understand the cause of the highly prevalent dyslipidemia. This will help guiding the early diagnosis, management, and prevention of cardiovascular complications.

High burden of recurrent cardiovascular events in heterozygous familial hypercholesterolemia: The French Familial Hypercholesterolemia Registry.

BACKGROUND AND AIMS: Cardiovascular risk is high in heterozygous familial hypercholesterolemia (HeFH). The objective of this study was to describe recurrent cardiovascular events in selected patients with HeFH attending lipid clinics in France. METHODS: We included 781 patients with a clinical (Dutch Lipid Clinic Network score ≥ 6) or genetic diagnosis of HeFH who had experienced a first cardiovascular event (myocardial infarction, percutaneous coronary intervention or coronary bypass, unstable angina, stroke, peripheral arterial revascularization or cardiovascular death) and were enrolled in the French Familial Hypercholesterolemia Registry (November 2015 to March 2018). RESULTS: The first cardiovascular event occurred at the mean age of 47 years (interquartile range 39-55) in a predominantly male population (72%); 48% of patients were on statin therapy. Overall, 37% of patients had at least one recurrent cardiovascular event (mean of 1.8 events per patient), of which 32% occurred in the 12 months after the index event; 55% of events occurred >3 years after the first event. Mean LDL-C at the last clinic visit was 144 ±â€¯75 mg/dL (132 ±â€¯69 mg/dL for patients on high-potency statin therapy and 223 ±â€¯85 mg/dL for untreated patients). CONCLUSIONS: The rate of recurrent cardiovascular events was high in French patients with HeFH in secondary prevention. The detection of FH during childhood is crucial to prevent CV events at a young age by early initiating statin therapy. There is a clear urgent need to expand the actual very small target population which can be treated with the PCSK9 inhibitor in France.

[Familial hypercholesterolemia: An under-diagnosed and under-treated disease. Survey of 495 physicians]. / Hypercholestérolémie familiale peu diagnostiquée, insuffisamment traitée. Enquête auprès de 495 médecins.

INTRODUCTION: Heterozygous familial hypercholesterolemia (FH) is one of the most frequent genetic diseases with a prevalence of 1/250. It is characterized by a very high cholesterol level since birth and is often complicated by cardiovascular diseases (CV) in young patients. While early diagnosis and appropriate therapeutic management can avoid CV complications, HF is largely under-diagnosed and therefore under-treated. METHODS: To investigate the management of HF in France, we conducted a survey with 495 general practitioners (n=200) and specialists (n=295). RESULTS: The results revealed: a large underestimation of the CV risk and a high therapeutic inertia in the management of the affected patients. The practitioners reported a real need for more information about the disease. CONCLUSION: Given the high frequency of HF and the associated cardiovascular morbidity and mortality, general practitioners have a decisive role to play for the identification and the management of these patients. The recent publication of HAS recommendations on family screening procedures and care of HF patients should improve the management of this disease.

Genetic diagnosis of familial hypercholesterolemia is associated with a premature and high coronary heart disease risk.

BACKGROUND: Familial hypercholesterolemia (FH) is a common autosomal dominant disease associated with premature coronary heart disease (CHD). Studies tend to show that patients with FH associated with an identified mutation (mutation+ FH) are at higher risk than patients without an identified mutation (mutation- FH). We compared the clinical and biological profile and the risk of CHD in patients with mutation+ FH and mutation- FH. HYPOTHESIS: In addition to LDL-C, a pathogenic mutation predicts premature CHD in FH. METHODS: We successively included all patients with suspected FH (LDL-C > 190 mg/dL if age > 18 years; LDL-C > 160 mg/dL if age < 18 years) and compared patients with a pathogenic mutation with those without an identified pathogenic mutation. RESULTS: We studied 179 patients with mutation+ FH and 147 with mutation- FH. The mean age was 44 (± 18) years. The lipid profile was more atherogenic in those with mutation+ FH, who had higher LDL-C (254 ± 69 mg/dL vs 218 ± 35 mg/dL; P < 0.01) and lower HDL-C (53 ± 14 mg/dL vs 58 ± 17 mg/dL; P < 0.01). Despite the more atherogenic nonlipid cardiovascular profile of patients with mutation- FH, the age of CHD onset was earlier in patients with mutation+ FH (48 vs 56 years; P = 0.026). After multiple adjustment, the presence of a positive mutation was significantly associated with premature CHD (OR: 3.0, 95% CI: 1.38-6.55, P < 0.01). CONCLUSIONS: Patients with mutation+ FH have a more atherogenic lipid profile and a 3-fold higher risk of premature CHD, as well as earlier onset of CHD, than patients with mutation- FH.

New Sequencing technologies help revealing unexpected mutations in Autosomal Dominant Hypercholesterolemia.

Autosomal dominant hypercholesterolemia (ADH) is characterized by elevated LDL-C levels leading to coronary heart disease. Four genes are implicated in ADH: LDLR, APOB, PCSK9 and APOE. Our aim was to identify new mutations in known genes, or in new genes implicated in ADH. Thirteen French families with ADH were recruited and studied by exome sequencing after exclusion, in their probands, of mutations in the LDLR, PCSK9 and APOE genes and fragments of exons 26 and 29 of APOB gene. We identified in one family a p.Arg50Gln mutation in the APOB gene, which occurs in a region not usually associated with ADH. Segregation and in-silico analysis suggested that this mutation is disease causing in the family. We identified in another family with the p.Ala3396Thr mutation of APOB, one patient with a severe phenotype carrying also a mutation in PCSK9: p.Arg96Cys. This is the first compound heterozygote reported with a mutation in APOB and PCSK9. Functional studies proved that the p.Arg96Cys mutation leads to increased LDL receptor degradation. This work shows that Next-Generation Sequencing (exome, genome or targeted sequencing) are powerful tools to find new mutations and identify compound heterozygotes, which will lead to better diagnosis and treatment of ADH.