Subjects with Molecularly Defined Familial Hypercholesterolemia or Familial Defective apoB-100 Are Not Being Adequately Treated

To study whether subjects with a molecular genetic diagnosis of familial hypercholesterolemia (FH) or familial defective apoB-100 (FDB) are being adequately treated.A questionnaire regarding medical history was sent to 2611 subjects who had been provided with a molecular genetic diagnosis of FH or FDB, and a blood sample was obtained for lipid measurements.956 (36.6%) of the 2611 subjects participated. The mean age for starting lipid-lowering therapy was 33.4 (±12.1) years. Among those below 18 years of age, only 20.4% were on lipid-lowering drugs, whereas 89.1% of those aged 18 and above were on lipid-lowering drugs. The mean levels of total serum cholesterol and LDL-cholesterol were 5.7 (±1.5) mmol/l and 3.9 (±1.3) mmol/l, respectively. Among those who were on lipid-lowering drugs, 29.0% and 12.2% had levels of LDL cholesterol below 3.0 mmol/l and 2.6 mmol/l, respectively. Only 47.3% of the 956 subjects were considered as being adequately treated largely due to a failure to titrate their drug regimens. From the use of cholesterol-years score, lipid-lowering therapy must start before the age of 20 in order to prevent the subjects from contracting premature coronary heart disease.The majority of FH/FDB subjects are being diagnosed late in life and are not being adequately treated. In order to prevent them from contracting premature coronary heart disease, it is key that levels of LDL cholesterol are normalized from a young age and that sufficient doses of lipid-lowering drugs are being used

Cascade testing in Familial Hypercholesterolaemia: how should family members be contacted?

Cascade testing or screening provides an important mechanism for identifying people at risk of a genetic condition. For some autosomal dominant conditions, such as Familial Hpercholesterolaemia (FH), identifying relatives allows for significant health-affecting interventions to be administered, which can extend a person’s life expectancy significantly. However, cascade screening is not without ethical implications. In this paper, we examine one ethically contentious aspect of cascade screening programmes, namely the alternative methods by which relatives of a proband can be contacted. Should the proband be responsible for contacting his or her family members, or should the screening programme contact family members directly? We argue that direct contact is an ethically justifiable method of contact tracing in cascade screening for FH. Not only has this method of contact already been utilised without adverse effects, an examination of the ethical arguments against it shows these are unsubstantiated. We describe several criteria which, if met, will allow an appropriate balance to be struck between maximising the efficiency of family tracing and respecting the interests of probands and their relatives. Keywords Cascade genetic screening; cascade testing; confidentiality; autonomy; genetics; ethics; guidelines; familial hypercholesterolaemi

Two years after molecular diagnosis of familial hypercholesterolemia: Majority on cholesterol-lowering treatment but a minority reaches treatment goal

Background: The risk of premature cardiovascular disease in patients with familial hypercholesterolemia (FH) can be profoundly reduced by cholesterol-lowering therapy, and current guidelines for FH advocate ambitious low-density lipoprotein cholesterol (LDL-C) goals. In the present study, we determined whether these goals are reflected in current clinical practice once FH has been diagnosed. Methodology/Principal Findings: In 2008, we sent questionnaires to all subjects (aged 18-65 years) who were molecularly diagnosed with FH in the year 2006 through the screening program in the Netherlands. Of these 1062 subjects, 781 completed the questionnaire (46% males; mean age: 42±12 years; mean LDL-C at molecular diagnosis (baseline): 4.1±1.3 mmol/L). The number of persons that used cholesterol-lowering therapy increased from 397 (51%) at baseline to 636 (81%) after diagnosis. Mean treated LDL-C levels decreased significantly to 3.2±1.1 mmol/L two years after diagnosis. Only 22% achieved the LDL-C target level of ≤2.5 mmol/L. Conclusions/Significance: The proportion of patients using cholesterol-lowering medication was significantly increased after FH diagnosis through

Patients’ Perceptions and Experiences of Familial Hypercholesterolemia, Cascade Genetic Screening and Treatment

Background: Familial hypercholesterolemia (FH) is a serious genetic disorder affecting approximately 1 in every 300 to 500 individuals and is characterised by excessively high low-density lipoprotein (LDL) cholesterol levels, substantially increased risk of early-onset coronary heart disease (CHD) and premature mortality. If FH is untreated, it leads to a greater than 50 % risk of CHD in men by the age of 50 and at least 30 % in women by the age of 60. FH can be diagnosed through genetic screening and effectively managed through pharmacological treatment and lifestyle changes. Purpose: Familial hypercholesterolemia (FH) is a genetic health condition that increases the risk of cardiovascular disease. Although FH can be effectively managed with appropriate pharmacological and dietary interventions, FH detection rate through genetic screening remains low. The present study explored perceptions and experiences of FH patients (N = 18) involved in a genetic cascade screening programme. Methods: Face-to-face interviews were conducted to assess patients’ knowledge and understanding of FH, explore factors linked to adherence to health-protective behaviours and examine perceptions of genetic screening. Results: Thematic analysis of interviews revealed four themes: disease knowledge, severity of FH, lifestyle behavioural change and barriers to cascade screening and treatment. Participants recognised FH as a permanent, genetic condition that increased their risk of CHD and premature mortality. Many participants dismissed the seriousness of FH and the importance of lifestyle changes because they perceived it to be effectively managed through medication. Despite positive attitudes toward screening, many participants reported that relatives were reluctant to attend screening due to their relatives’ ‘fatalistic’ outlook or low motivation. Participants believed that they had insufficient authority or control to persuade family members to attend screening and welcomed greater hospital assistance for contact with relatives. Conclusions: Findings support the adoption of direct methods of recruitment to cascade screening led by medical professionals, who were perceived as having greater authority. Other implications included the need for clinicians to provide clear information, particularly to those who are asymptomatic, related to the seriousness of FH and the necessity for adherence to medication and lifestyle changes

A Locked Nucleic Acid Antisense Oligonucleotide (LNA) Silences PCSK9 and Enhances LDLR Expression In Vitro and In Vivo

The proprotein convertase subtilisin/kexin type 9 (PCSK9) is an important factor in the etiology of familial hypercholesterolemia (FH) and is also an attractive therapeutic target to reduce low density lipoprotein (LDL) cholesterol. PCSK9 accelerates the degradation of hepatic low density lipoprotein receptor (LDLR) and low levels of hepatic PCSK9 activity are associated with reduced levels of circulating LDL-cholesterol.The present study presents the first evidence for the efficacy of a locked nucleic acid (LNA) antisense oligonucleotide (LNA ASO) that targets both human and mouse PCSK9. We employed human hepatocytes derived cell lines HepG2 and HuH7 and a pancreatic mouse beta-TC3 cell line known to express high endogenous levels of PCSK9. LNA ASO efficiently reduced the mRNA and protein levels of PCSK9 with a concomitant increase in LDLR protein levels after transfection in these cells. In vivo efficacy of LNA ASO was further investigated in mice by tail vein intravenous administration of LNA ASO in saline solution. The level of PCSK9 mRNA was reduced by approximately 60%, an effect lasting more than 16 days. Hepatic LDLR protein levels were significantly up-regulated by 2.5-3 folds for at least 8 days and approximately 2 fold for 16 days. Finally, measurement of liver alanine aminotransferase (ALT) levels revealed that long term LNA ASO treatment (7 weeks) does not cause hepatotoxicity.LNA-mediated PCSK9 mRNA inhibition displayed potent reduction of PCSK9 in cell lines and mouse liver. Our data clearly revealed the efficacy and safety of LNA ASO in reducing PCSK9 levels, an approach that is now ready for testing in primates. The major significance and take home message of this work is the development of a novel and promising approach for human therapeutic intervention of the PCSK9 pathway and hence for reducing some of the cardiovascular risk factors associated with the metabolic syndrome

A functional polymorphism in the promoter region of the microsomal triglyceride transfer protein (MTP -493G/T) influences lipoprotein phenotype in familial hypercholesterolemia.

The microsomal triglyceride transfer protein (MTP) has a key function in intracellular apolipoprotein (apo) B lipidation and secretion of very low density lipoprotein (VLDL). A recently discovered functional polymorphism in the promoter of the MTP gene (-493G/T) affects the plasma concentration of low density lipoprotein (LDL) cholesterol and the VLDL distribution between large and small particle species in healthy men. This phenotype is likely to be explained by an effect on VLDL synthesis. Against this background, we studied the effect of the MTP-493G/T polymorphism in a large cohort (217 men and 211 women) with heterozygous familial hypercholesterolemia (FH). A 40% to 50% lower serum triglyceride level was observed in homozygous carriers of the MTP-493 T allele (T/T, 0.93+/-0.34; G/T, 1.54+/-1.40; and G/G, 1.56+/-1.24 mmol/L; T/T vs G/T P=0.04, T/T vs G/G P=0.02). In contrast to the situation in healthy subjects, the MTP promoter polymorphism did not have a significant effect on the LDL cholesterol levels in FH subjects, although the same trend was observed (T/T, 7.31+/-1.87; G/T, 7. 80+/-2.12; and G/G, 7.91+/-2.31 mmol/L, NS). Adjustment for the apo E gene polymorphism by inclusion of subjects homozygous for the apo E3 allele only revealed a reciprocal high density lipoprotein cholesterol-elevating effect (T/T, 1.41+/-0.73; G/T, 1.18+/-0.27; and G/G, 1.16+/-0.29 mmol/L; T/T vs G/T P=0.06, T/T vs G/G P=0.04). This effect seemed to be sex-specific because it was accounted for by the female patients. In conclusion, the LDL cholesterol-lowering effect of the rare MTP gene promoter variant (MTP-493T) present in healthy subjects is shifted to a triglyceride-lowering effect in FH. These data suggest that the MTP gene has a role in modulating the clinical phenotype of FH

Development of sensitive and specific age- and gender-specific low-density lipoprotein cholesterol cutoffs for diagnosis of first-degree relatives with familial hypercholesterolaemia in cascade testing.

BACKGROUND: The plasma total and low-density lipoprotein-cholesterol (LDL-C) levels that are used as diagnostic criteria for familial hypercholesterolaemia (FH) probands in the general population are too stringent for use in relatives, given the higher prior probability of a first-degree relative being FH (50% vs. 1/500). Our objective was therefore to develop more appropriate LDL-C cutoffs to identify "affected" first-degree relatives found by cascade testing, to test their accuracy and utility in case identification, and to compare them with the published "Make early diagnosis to prevent disease" (MEDPED) cutoffs from the US. METHODS: Using a large, anonymised sample of genetically tested first-degree relatives of Netherlands FH probands (mutation carriers/non-carriers, n=825/2,469), age- and gender-specific LDL-C diagnostic cutoffs for first-degree relatives were constructed. These were used to test similar data from Denmark (n=160/161) and Norway (n=374/742). RESULTS: Gender-specific LDL-C diagnostic cutoffs were established for six different age groups, which achieved an overall accuracy (measured as Youden's index) of 0.53 in the Netherlands data, and performed significantly better amongst younger (<25 years) compared to older first-degree relatives (0.68 vs. 0.42 Youden's index, p<0.001). Compared with the Netherlands data, age- and gender-adjusted mean LDL-C levels were significantly higher (approximately 0.5 mmol/L) in the Denmark and Norway subjects for both mutation carriers and non-carriers. After adjusting for this difference, the LDL-C cut-offs showed a similar accuracy in identifying mutation carriers from Denmark (81%, range 78%-86%) and Norway (84%, range 82%-86%). Although the MEDPED cutoffs performed significantly worse than these for the Netherlands data (p<0.001), they performed equally well in overall accuracy for the Norwegian and Danish data, although the LDL-C cutoffs had a significantly higher sensitivity but lower specificity for all three countries. CONCLUSIONS: The cutoffs developed here are designed to give the greatest overall accuracy when testing relatives of FH patients in the absence of a genetic diagnosis. They have a more balanced specificity and sensitivity than the MEDPED cutoffs that are designed to achieve higher specificity, which is more appropriate for cascade testing purposes. The data suggest that country-specific LDL-C cutoffs may lead to greater accuracy for identifying FH patients, but should be used with caution and only when a genetic diagnosis (DNA) is not available