Comparison of the characteristics at diagnosis and treatment of children with heterozygous familial hypercholesterolaemia (FH) from eight European countries

Background and aims: For children with heterozygous familial hypercholesterolaemia (HeFH), European guidelines recommend consideration of statin therapy by age 8–10 years for those with a low density lipoprotein cholesterol (LDL-C) >3.5 mmol/l, and dietary and lifestyle advice. Here we compare the characteristics and lipid levels in HeFH children from Norway, UK, Netherlands, Belgium, Czech Republic, Austria, Portugal and Greece. Methods: Fully-anonymized data were analysed at the London centre. Differences in registration and on treatment characteristics were compared by standard statistical tests. Results: Data was obtained from 3064 children. The median age at diagnosis differed significantly between countries (range 3–11 years) reflecting differences in diagnostic strategies. Mean (SD) LDL-C at diagnosis was 5.70 (±1.4) mmol/l, with 88% having LDL-C>4.0 mmol/l. The proportion of children older than 10 years at follow-up who were receiving statins varied significantly (99% in Greece, 56% in UK), as did the proportion taking Ezetimibe (0% in UK, 78% in Greece). Overall, treatment reduced LDL-C by between 28 and 57%, however, in those >10 years, 23% of on-treatment children still had LDL-C>3.5 mmol/l and 66% of those not on a statin had LDL-C>3.5 mmol/l. Conclusions: The age of HeFH diagnosis in children varies significantly across 8 countries, as does the proportion of those >10 years being treated with statin and/or ezetimibe. Approximately a quarter of the treated children and almost three quarters of the untreated children older than 10 years still have LDL-C concentrations over 3.5 mmol/l. These data suggest that many children with FH are not receiving the full potential benefit of early identification and appropriate lipid-lowering treatment according to recommendations

Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life

Familial hypercholesterolaemia in children and adolescents from 48 countries : a cross-sectional study

Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11848 individuals. Median age at registry entry was 9·6 years (IQR 5·8–13·2). 10 099 (89·9%) of 11235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05–6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50–75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life.peer-reviewe

Statins for children with familial hypercholesterolemia

Background Familial hypercholesterolemia is one of the most common inherited metabolic diseases and is an autosoma dominant disorder meaning heterozygotes, or carriers, are affected. Those who are homozygous have severe disease. The average worldwide prevalence of heterozygous familial hypercholesterolemia is at least 1 in 500, although recent genetic epidemiological data from Denmark and next generation sequencing data suggest the frequency may be closer to 1 in 250. Diagnosis of familial hypercholesteroemia in children is based on elevated total cholesterol and low-density ipoprotein cholesterol levels or DNA-based analysis, or both. Coronary atherosclerosis has been detected in men with heterozygous familial hypercholesterolemia as young as 17 years old and in women with heterozygous familial hypercholesterolemia at 25 years old. Since the clinical complications of atherosclerosis occur prematurely, especially in men, lifelong treatment, started in childhood, is needed to reduce the risk of cardiovascular disease. In children with the disease, diet was the cornerstone of treatment but the addition of lipid-lowering medications has resulted in a significant improvement in treatment. Anion exchange resins, such as cholestyramine and colestipol, were found to be effective, but they are poorly tolerated. Since the 1990s studies carried out on children aged 6 to 17 years with heterozygous familial hypercholesterolemia have demonstrated significant reductions in their serum total and low-density lipoprotein cholesterol levels. While statins seem to be safe and well-tolerated in children, their long-term safety in this age group is not firmly established. This is an update of a previously published version of this Cochane Review. Objectives To assess the effectiveness and safety of statins in children with heterozygous familial hypercholesterolemia. Search methods Relevant studies were identified from the Group's Inborn Errors and Metabolism Trials Register and Medline. Date of most recent search: 04 November 2019. Selection criteria Randomized and controlled clinical studies including participants up to 18 years old, comparing a statin to placebo or to diet alone. Data collection and analysis Two authors independently assessed studies for inclusion and extracted data. Main results We found 26 potentially eligible studies, of which we included nine randomized placebo-controlled studies (1177 participants). Ingeneral, the intervention and follow-up time was short (median 24 weeks; range from six weeks to two years). Statins reduced the mean low-density lipoprotein cholesterol concentration at all time points (high-quality evidence). There may be little or no difference in liverfunction (serum aspartate and alanine aminotransferase, as well as creatinine kinase concentrations) between treated and placebo groups at any time point (low-quality evidence). There may be little or no difference in myopathy (as measured in change in creatinine levels) (low-quality evidence) or clinical adverse events (moderate-quality evidence) with statins compared to placebo. One study on simvastatin showed that this may slightly improve flow-mediated dilatation of the brachial artery (low-quality evidence), and on pravastatin for two years may have induced a regression in carotid intima media thickness (low-quality evidence). No studies reported rhabdomyolysis (degeneration of skeletal muscle tissue) or death due to rhabdomyolysis, quality of life or compliance to study medication. Authors' conclusions Statin treatment is an effective lipid-lowering therapy in children with familial hypercholesterolemia. Few or no safety issues were identified. Statin treatment seems to be safe in the short term, but long-term safety remains unknown. Children treated with statins should be carefully monitored and followed up by their pediatricians and their care transferred to an adult lipidologist once they reach 18 years of age. Large long-term randomized controlled trials are needed to establish the long-term safety issues of statins. PLAIN LANGUAGE SUMMARY Statins for children with inherited high blood cholesterol Review question We reviewed the evidence for the effectiveness and safety of statins in children with inherited high blood cholesterol. Background Familial hypercholesterolemia is an inherited disease in which the blood cholesterol level is high. Vascular disease, i.e. furring up of the blood vessels, often occurs at an earlier age than usual, especially amongst men. Thus lifelong therapies, started in childhood, to reduce blood cholesterol are needed. In children with familial hypercholesterolemia, diet has been the main treatment option. Medications, such as cholestyramine and colestipol, have been used effectively, but due to their unpleasant taste they are poorly tolerated and treatment plans are not followed. The advent of statin therapy for children has improved treatment and this review updates the previous published version. Search date The evidence is current to: 04 November 2019. Study characteristics The review included 9 studies with 1177 people with heterozygous familial hypercholesterolemia aged between 4 and 18 years of age. Studies compared different statin treatments with a substance which contains no medication (termed placebo) and people were selected for one treatment or the other randomly. The studies lasted from 12 weeks to 104 weeks. Key results In general, the intervention and follow-up time was short (median 24 weeks; range from six weeks to two years). Statins probably reduced the mean low-density lipoprotein cholesterol concentration at all time points (moderate-quality evidence). The levels of the liver enzymes, serum aspartate and alanine aminotransferase, and the muscle enzyme, creatinine kinase, did not differ between treated and placebo groups at any time point (low-quality evidence). The risks of myopathy (disease of muscle tissue) and side-effects were very low and similar in both groups (low-quality evidence). Two of the statins, simvastatin and pravastatin may have a positive effect on two of the major blood vessels typically affected by raised cholesterol levels (low-quality evidence). Quality of the evidence Information regarding blinding (performance bias and detection bias), was available for all nine studies; each was described as double blind, indicating that participants and those participating in treatment procedures were blinded to treatment. In two studies information on how the participants were allocated to treatment groups (selection bias) was clearly presented, but this information was not clearly stated in the remaining seven studies. There is a lack of information whether investigators knew which treatment group participants would be put into (selection bias) and or whether selective reporting (reporting bias) occurred, but it is very unlikely. In conclusion, it can be stated all the studies appeared to be well run and we do not think any of the above-mentioned factors influenced the results in a negative way. Quality of evidence varied from moderate (change in serum low-density lipoprotein (LDL) cholesterol and adverse events) to low (change in blood vessel wall (carotid intima-media) thickness, change in measures if growth and maturation, liver dysfunction, myopathy and change in blood wall (endothelial) function).Peer reviewe

Statins for children with familial hypercholesterolemia

Background Familial hypercholesterolemia is one of the most common inherited metabolic diseases; the average worldwide prevalence of heterozygous familial hypercholesterolemia is at least 1 in 500. Diagnosis of familial hypercholesterolemia in children is based on highly elevated low-density lipoprotein (LDL) cholesterol level or DNA-based analysis, or both. Coronary atherosclerosis has been detected in men with heterozygous familial hypercholesterolemia as young as 17 years old and in women with heterozygous familial hypercholesterolemia at 25 years old. Since the clinical complications of atherosclerosis occur prematurely, especially in men, lifelong hypolipidemic measures, started in childhood, are needed to reduce the risk of cardiovascular disease. In children with familial hypercholesterolemia, diet is as yet the cornerstone of treatment. Anion exchange resins, such as cholestyramine and colestipol, have also been found to be effective, but are poorly tolerated. Since the 1990s statin studies have been carried out among children with familial hypercholesterolemia (aged 7 to 17 years). Statins greatly reduced their serum LDL cholesterol levels. Even though statins seem to be safe and well-tolerated in children, their long-term safety in this age group is not firmly established. Objectives To assess the effectiveness and safety of statins in children with familial hypercholesterolemia. Search methods Relevant studies were identified from the Group’s Inborn Errors and Metabolism Trials Register and Medline. Date of most recent search: 14 October 2013. Selection criteria Randomized and controlled clinical studies including participants up to 18 years old, comparing a statin to placebo or to diet alone. Data collection and analysis Two authors independently assessed studies for inclusion and extracted data. Main results We found 21 potentially eligible studies, of which we included eight randomized placebo-controlled studies (1074 participants). In general, the intervention and follow-up time was short (median 24 weeks; range from six weeks to two years). Statins reduced the mean LDL cholesterol concentration at all time points. Serum aspartate and alanine aminotransferase, as well as creatinine kinase concentrations, did not differ between treated and placebo groups at any time point. The risks of myopathy and clinical adverse events were very low and also similar in both groups. In one study simvastatin was shown to improve flow-mediated dilatation of the brachial artery, and in another study treatment with pravastatin for two years induced a significant regression in carotid intima media thickness. Authors’ conclusions Statin treatment is an efficient lipid-lowering therapy in children with familial hypercholesterolemia. No significant safety issues were identified. Statin treatment seems to be safe in the short term, but long-term safety is unknown. Children treated with statins should be carefully monitored and followed up by their pediatricians or physicians into adulthood. Large long-term randomized controlled trials are needed to establish the long-term safety issues of statins

Comparison of the mutation spectrum and association with pre and post treatment lipid measures of children with heterozygous familial hypercholesterolaemia (FH) from eight European countries.

Familial hypercholesterolaemia (FH) is commonly caused by mutations in the LDLR, APOB or PCSK9 genes, with untreated mean low density lipoprotein-cholesterol (LDL-C) concentrations being elevated in APOB mutation carriers, even higher in LDLR mutation and highest in those with a PCSK9 mutation. Here we examine this in children with FH from Norway, UK, The Netherlands, Belgium, Czech Republic, Austria, Portugal and Greece. Differences in characteristics and pre- and post-treatment lipid concentrations in those with different molecular causes were compared by standard statistical tests. Data were obtained from 2866 children, of whom 2531 (88%) carried a reported LDLR/APOB/PCSK9 variant. In all countries, the most common cause of FH was an LDLR mutation (79% of children, 297 different), but the prevalence of the APOB p.(Arg3527Gln) mutation varied significantly (ranging from 0% in Greece to 39% in Czech Republic, p < 2.2 × 10). The prevalence of a family history of premature CHD was significantly higher in children with an LDLR vs APOB mutation (16% vs 7% p=0.0005). Compared to the LDLR mutation group, mean (±SD) concentrations of pre-treatment LDL-C were significantly lower in those with an APOB mutation (n = 2260 vs n = 264, 4.96 (1.08)mmol/l vs 5.88 (1.41)mmol/l, p < 2.2 × 10) and lowest in those with a PCSK9 mutation (n = 7, 4.71 (1.22)mmol/l). The most common cause of FH in children from eight European countries was an LDLR mutation, with the prevalence of the APOB p.(Arg3527Gln) mutation varying significantly across countries. In children, LDLR-FH is associated with higher concentrations of LDL-C and family history of CHD compared to those with APOB-FH

Comparison of the mutation spectrum and association with pre and post treatment lipid measures of children with heterozygous familial hypercholesterolaemia (FH) from eight European countries

Background and aims: Familial hypercholesterolaemia (FH) is commonly caused by mutations in the LDLR, APOB or PCSK9 genes, with untreated mean low density lipoprotein-cholesterol (LDL-C) concentrations being elevated in APOB mutation carriers, even higher in LDLR mutation and highest in those with a PCSK9 mutation. Here we examine this in children with FH from Norway, UK, The Netherlands, Belgium, Czech Republic, Austria, Portugal and Greece. Methods: Differences in characteristics and pre- and post-treatment lipid concentrations in those with different molecular causes were compared by standard statistical tests. Results: Data were obtained from 2866 children, of whom 2531 (88%) carried a reported LDLR/APOB/PCSK9 variant. In all countries, the most common cause of FH was an LDLR mutation (79% of children, 297 different), but the prevalence of the APOB p.(Arg3527Gln) mutation varied significantly (ranging from 0% in Greece to 39% in Czech Republic, p < 2.2 × 10-16). The prevalence of a family history of premature CHD was significantly higher in children with an LDLR vs APOB mutation (16% vs 7% p=0.0005). Compared to the LDLR mutation group, mean (±SD) concentrations of pre-treatment LDL-C were significantly lower in those with an APOB mutation (n = 2260 vs n = 264, 4.96 (1.08)mmol/l vs 5.88 (1.41)mmol/l, p < 2.2 × 10-16) and lowest in those with a PCSK9 mutation (n = 7, 4.71 (1.22)mmol/l). Conclusions: The most common cause of FH in children from eight European countries was an LDLR mutation, with the prevalence of the APOB p.(Arg3527Gln) mutation varying significantly across countries. In children, LDLR-FH is associated with higher concentrations of LDL-C and family history of CHD compared to those with APOB-FH.Highlights: LDLR mutations are the most common cause of familial hypercholesterolaemia (FH) in children from 8 European countries; Overall, 279 different LDLR mutations were found in 2531 FH children; The frequency of APOB p.(Arg3527Gln) varied significantly over the 8 countries; APOB-FH was less severe than LDLR-FH for low density lipoprotein-cholesterol (LDL-C) concentration and family onset of coronary heart disease (CHD).The European Register is supported by a grant from the International Atherosclerosis Society (Pfizer number 24052829). The UK register is supported by funds from the British Heart Foundation (BHF); HEART UK, Cardiac Network Co-ordinating Group Wales and the Royal College of Physicians. SEH is a BHF Professor and is funded by PG08/008, and by the National Institute for Health Research University College London Hospitals Biomedical Research Centre. MF is funded by the Fondation Leducq Transatlantic Networks of Excellence Program grant (no. 14 CVD03). MV is supported by the Ministry of Health, Czechia, project No. 64165, General University Hospital in Prague. TF and LT are supported by the Ministry of Health, Czechia, grant number NU20-02-00261. The Austrian FH register has been supported by funds from the Austrian Heart Foundation and the Tyrolean Regional Government. The Portuguese FH Study has been supported by grants from the Portuguese Science and Technology Foundation and grants from the Portuguese Cardiology Society. AMM was supported by the Portuguese Science and Technology Foundation, grant number SFRH/BD/113,017/2015. The study sponsors had no role in study design, the collection, analysis, and interpretation of data, the writing of the report or the decision to submit the manuscript for publication. No honorarium, grant, or other form of payment was given to anyone to produce the manuscript.info:eu-repo/semantics/publishedVersio

Comparison of the mutation spectrum and association with pre and post treatment lipid measures of children with heterozygous familial hypercholesterolaemia (FH) from eight European countries

Background and aims: Familial hypercholesterolaemia (FH) is commonly caused by mutations in the LDLR, APOB or PCSK9 genes, with untreated mean low density lipoprotein-cholesterol (LDL-C) concentrations being elevated in APOB mutation carriers, even higher in LDLR mutation and highest in those with a PCSK9 mutation. Here we examine this in children with FH from Norway, UK, The Netherlands, Belgium, Czech Republic, Austria, Portugal and Greece. Methods: Differences in characteristics and pre- and post-treatment lipid concentrations in those with different molecular causes were compared by standard statistical tests. Results: Data were obtained from 2866 children, of whom 2531 (88%) carried a reported LDLR/APOB/PCSK9 variant. In all countries, the most common cause of FH was an LDLR mutation (79% of children, 297 different), but the prevalence of the APOB p.(Arg3527Gln) mutation varied significantly (ranging from 0% in Greece to 39% in Czech Republic, p < 2.2 × 10 −16). The prevalence of a family history of premature CHD was significantly higher in children with an LDLR vs APOB mutation (16% vs 7% p=0.0005). Compared to the LDLR mutation group, mean (±SD) concentrations of pre-treatment LDL-C were significantly lower in those with an APOB mutation (n = 2260 vs n = 264, 4.96 (1.08)mmol/l vs 5.88 (1.41)mmol/l, p < 2.2 × 10 −16) and lowest in those with a PCSK9 mutation (n = 7, 4.71 (1.22)mmol/l). Conclusions: The most common cause of FH in children from eight European countries was an LDLR mutation, with the prevalence of the APOB p.(Arg3527Gln) mutation varying significantly across countries. In children, LDLR-FH is associated with higher concentrations of LDL-C and family history of CHD compared to those with APOB-FH

Refinement of variant selection for the LDL cholesterol genetic risk score in the diagnosis of the polygenic form of clinical familial hypercholesterolemia and replication in samples from 6 countries.

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal-dominant disorder caused by mutations in 1 of 3 genes. In the 60% of patients who are mutation negative, we have recently shown that the clinical phenotype can be associated with an accumulation of common small-effect LDL cholesterol (LDL-C)-raising alleles by use of a 12-single nucleotide polymorphism (12-SNP) score. The aims of the study were to improve the selection of SNPs and replicate the results in additional samples. METHODS: We used ROC curves to determine the optimum number of LDL-C SNPs. For replication analysis, we genotyped patients with a clinical diagnosis of FH from 6 countries for 6 LDL-C-associated alleles. We compared the weighted SNP score among patients with no confirmed mutation (FH/M-), those with a mutation (FH/M+), and controls from a UK population sample (WHII). RESULTS: Increasing the number of SNPs to 33 did not improve the ability of the score to discriminate between FH/M- and controls, whereas sequential removal of SNPs with smaller effects/lower frequency showed that a weighted score of 6 SNPs performed as well as the 12-SNP score. Metaanalysis of the weighted 6-SNP score, on the basis of polymorphisms in CELSR2 (cadherin, EGF LAG 7-pass G-type receptor 2), APOB (apolipoprotein B), ABCG5/8 [ATP-binding cassette, sub-family G (WHITE), member 5/8], LDLR (low density lipoprotein receptor), and APOE (apolipoprotein E) loci, in the independent FH/M- cohorts showed a consistently higher score in comparison to the WHII population (P 95% likelihood of a polygenic explanation of their increased LDL-C. CONCLUSIONS: A 6-SNP LDL-C score consistently distinguishes FH/M- patients from healthy individuals. The hypercholesterolemia in 88% of mutation-negative patients is likely to have a polygenic basis

Refinement of variant selection for the LDL cholesterol genetic risk score in the diagnosis of the polygenic form of clinical familial hypercholesterolemia and replication in samples from 6 countries

Background: Familial hypercholesterolemia (FH) is an autosomal-dominant disorder caused by mutations in 1 of 3 genes. In the60%of patients who are mutation negative, we have recently shown that the clinical phenotype can be associated with an accumulation of common small-effect LDL cholesterol (LDL-C)-raising alleles by use of a 12-single nucleotide polymorphism (12-SNP) score. The aims of the study were to improve the selection of SNPs and replicate the results in additional samples.Methods: We used ROC curves to determine the optimum number of LDL-C SNPs. For replication analysis, we genotyped patients with a clinical diagnosis of FH from 6 countries for 6 LDL-C-associated alleles. We compared the weighted SNP score among patients with no confirmed mutation (FH/M-), those with amutation(FH/M-), and controls from aUK population sample (WHII).Results: Increasing the number of SNPs to 33 did not improve the ability of the score to discriminate between FH/M-and controls, whereas sequential removal of SNPs with smaller effects/lower frequency showed that a weighted score of 6 SNPs performed as well as the 12-SNP score. Metaanalysis of the weighted 6-SNP score, on the basis of polymorphisms in CELSR2 (cadherin, EGF LAG 7-pass G-type receptor 2), APOB (apolipoprotein B), ABCG5/8 [ATP-binding cassette, sub-family G (WHITE), member 5/8], LDLR (low density lipoprotein receptor), and APOE (apolipoprotein E) loci, in the independent FH/M-cohorts showed a consistently higher score in comparison to the WHII population (P95% likelihood of a polygenic explanation of their increased LDL-C.Conclusions: A 6-SNP LDL-C score consistently distinguishes FH/M-patients from healthy individuals. The hypercholesterolemia in 88% of mutation-negative patients is likely to have a polygenic basis