Aortic valve and arterial calcification in patients with familial hypercholesterolemia.

Heterozygous familial hypercholesterolemia (heFH) is an autosomal dominant lipid metabolism disorder. Its prevalence is 1:250-1:300 people in the population. Patients with heFH have an up to 13-fold increased risk of premature coronary artery disease (CAD). If left untreated, men and women with heFH typically develop early CAD before the ages of 55 and 60, respectively. There is evidence that coronary artery calcification (CAC) and aortic valve calcification (AoVC) are more prevalent in FH patients than in the general population. It is documented that CAC and AoVC are predictors of increased risk of cardiovascular morbidity and mortality in heFH patients, like in the general population. However, the etiology and pathogenesis of vascular calcification in FH patients is not well understood. Risk factors for vascular calcification include age, increased levels of atherogenic lipoproteins, Lp(a), increased blood pressure, and inflammation. There are convincing data from clinical studies and animal atherosclerotic mouse models using low-density lipoprotein receptor (LDL-R) knockout mice that the vascular calcification processes in FH are associated with LDL-R mutations, probably partly due to a higher total cholesterol burden of FH subjects. Data from animal models as well as clinical studies indicate that the Wnt/beta-catenin pathway components and LDL receptor-related proteins 5 and 6 (LRP-5/6) might be involved in calcification processes in FH patients. The purpose of the review is to describe the prevalence of coronary and aortic calcification and its risk factors in FH patients. The review covers data about the role of the Wnt/beta-catenin pathway and factors modulating calcification processes.

Targeted sequencing of a gene panel in patients with familial hypercholesterolemia from Southern Poland.

INTRODUCTION: Familial hypercholesterolemia (FH) is an autosomal dominant monogenic lipid metabolism disorder characterized by a significantly elevated level of low­density lipoprotein (LDL) cholesterol and leading to premature ischemic heart disease. FH is caused by mutations in the LDLR, APOB, and PCSK9 genes; however, these mutations account for only about 40% of FH cases. In order to obtain a genetic diagnosis of FH, sequencing of other genes involved in the lipid metabolism might be useful. OBJECTIVES: This study aimed to describe genetic variants in genes associated with FH in a group of patients from the Malopolska province in Southern Poland, using the targeted next generation sequencing (NGS) technology. PATIENTS AND METHODS: The study involved 90 unrelated adults (age range, 18-70 years) with FH diagnosed clinically according to the Simon Broome Register criteria. A custom­designed capture assay and the Illumina MiSeq platform were used. The panel included exons and exon / intron boundaries of known FH­causing genes: LDLR, APOB, and PCSK9, as well as genes previously associated with high cholesterol levels: APOE, ABCG5, ABCG8, LPL, NPC1, LDLRAP1, LIPC, STAP1, and CELSR2. Genetic variants were classified based on in silico predictions and ClinVar reports. RESULTS: We detected 4 patients with variants in the LDLR and APOB genes that had not been previously linked to FH in ClinVar. We also found APOB mutations outside the common LDL receptor-binding region, in exons 26 and 29. Interestingly, we observed a high frequency of pathogenic variants in exon 4 of the APOE gene: rs7412, probably damaging (4 patients) and rs429358, benign (16 patients). CONCLUSIONS: NGS is a useful and reliable method to detect new variants in genes related to FH. In addition, the results enable the detection of FH phenocopies and introduction of appropriate treatment.

The genetic spectrum of familial hypercholesterolemia in south-eastern Poland.

BACKGROUND: Familial hypercholesterolemia (FH) is a common autosomal dominant disorder with a frequency of 1 in 200 to 500 in most European populations. Mutations in LDLR, APOB and PCSK9 genes are known to cause FH. In this study, we analyzed the genetic spectrum of the disease in the understudied Polish population. MATERIALS AND METHODS: 161 unrelated subjects with a clinical diagnosis of FH from the south-eastern region of Poland were recruited. High resolution melt and direct sequencing of PCR products were used to screen 18 exons of LDLR, a region of exon 26 in the APOB gene and exon 7 of PCSK9. Multiplex ligation-dependent probe amplification (MLPA) was performed to detect gross deletions and insertions in LDLR. Genotypes of six LDL-C raising SNPs were used for a polygenic gene score calculation. RESULTS: We found 39 different pathogenic mutations in the LDLR gene with 10 of them being novel. 13 (8%) individuals carried the p.Arg3527Gln mutation in APOB, and overall the detection rate was 43.4%. Of the patients where no mutation could be found, 53 (84.1%) had a gene score in the top three quartiles of the healthy comparison group suggesting that they have a polygenic cause for their high cholesterol. CONCLUSIONS: These results confirm the genetic heterogeneity of FH in Poland, which should be considered when designing a diagnostic strategy in the country. As in the UK, in the majority of patients where no mutation can be found, there is likely to be a polygenic cause of their high cholesterol level.

Intima-media thickness correlates with features of metabolic syndrome in young people with a clinical diagnosis of familial hypercholesterolaemia.

BACKGROUND: Familial hypercholesterolaemia (FH) is a monogenic lipid metabolism disorder characterised by markedly elevated serum low-density lipoprotein (LDL) cholesterol level due to a mutation in the LDL receptor gene. Clinical features of FH include premature atherosclerosis and coronary artery disease. AIM: To explore associations between noninvasive markers of atherosclerosis including intima-media thickness (IMT) and pulse wave velocity (PWV) and blood lipids, blood pressure (BP) and obesity in a group of young patients with FH. METHODS: Study population included 36 patients aged < 35 years with the diagnosis of FH based on the Simon Broome Register criteria, and their 49 relatives who comprised the control group free of FH. RESULTS: Mean IMT values were higher in FH patients than controls (0.60 ± 0.19 vs. 0.53 ± 0.07 mm, respectively, p < 0.05).Mean body mass index (BMI) and waist circumference were similar in patients and controls. The prevalence of carotid atherosclerotic plaques was significantly higher among FH patients (n = 6) than in controls (n = 1) (21.4% vs. 2.6%, p = 0.012). Arterial hypertension was present in 27.8% of patients with FH and 16.3% of subjects in the control group. Systolic blood pressure (SBP) in FH patients correlated significantly with age (r = 0.35), BMI (r = 0.48) and waist circumference (r = 0.47), and diastolic blood pressure (DBP) correlated with BMI (r = 0.42) and waist circumference (r = 0.41). PWV correlated significantly with age (r = 0.44), SBP (r = 0.63) and DBP (r = 0.52). We did not find any correlations between IMT and serum lipids, BP or obesity indices in FH patients. CONCLUSIONS: Our findings show a higher rate of arterial hypertension in young FH patients compared to their relatives free of FH, with significant associations between BP and indices of obesity and arterial stiffness. Intensive lipid lowering and antihypertensive therapy along with a reduction in central fat may be considered a mandatory treatment strategy in young FH patients to prevent atherosclerosis and increased arterial stiffness.

Management of familial heterozygous hypercholesterolemia: Position Paper of the Polish Lipid Expert Forum.

Heterozygous familial hypercholesterolemia (HFH) affects on average 1 in 500 individuals in European countries, and it is estimated that HeFH in Poland may affect more than 80,000 people. Cardiovascular mortality in individuals with FH between 20 and 39 years of age is 100 times higher than in the general population. HFH is a relatively common lipid disorder, but usually still remaining undiagnosed and untreated. A very high risk of cardiovascular diseases and a shortened lifespan in patients with this condition require early diagnosis and intensive treatment. The aim of the position paper was to present the importance and scale of this problem in Poland, which has not been raised enough so far, as well as the recommendations of diagnosis, treatment and prevention methods.

A novel mutation (Cys308Phe) of the LDL receptor gene in families from the South-Eastern part of Poland.

The purpose of this investigation was to characterize a new mutation in the LDL-receptor (LDLR) gene in three families with clinically diagnosed familial hypercholesterolemia (FH) from the South-Eastern part of Poland. Mutational screening with exon by exon sequencing analysis was performed in all probands. The novel mutation c986G>T (Cys308Phe) in the exon 7 of LDLR gene was found in three apparently unrelated probands with FH. Analysis of the receptor activity of peripheral blood lymphocytes by binding and uptake of DiL-LDL showed a significant reduction (by 24% versus healthy control) of the fluorescent label in the lymphocytes of patients heterozygous for this mutation. Concentrations of serum LDL-C in probands before treatment were between 9.5 and 10.5 mmol/l. All patients had corneal arcus and tendon xanthoma. Clinically, families were characterized by premature coronary artery disease. This mutation occurred relatively frequently in our group of patients with FH, but this could be explained by a founder effect since we demonstrated their common ancestors.

Corticosteroid treatment of kidney disease in a patient with familial lecithin-cholesterol acyltransferase deficiency.

Familial lecithin-cholesterol acyltransferase (LCAT) deficiency (FLD) is a rare genetic disorder of lipid metabolism, characterised by low plasma HDL cholesterol, proteinuria, haemolytic anaemia and corneal opacities. Usually renal disease progresses during the third decade of life to renal failure; however the pathogenesis of renal disease is not well understood. In this study we describe treatment of renal disease in two siblings with FLD. The proband WX at the age of 31 years presented proteinuria and ankle oedema during her third pregnancy. Diagnosis of FLD was based on a renal biopsy with characteristic serpiginous fibrillar deposits under electron microscopy, markedly decreased HDL cholesterol, esterified cholesterol levels and LCAT activity, confirmed by molecular analysis. After 3 years her proteinuria increased and she received an ACE inhibitor to which she responded well. During further increases of proteinuria she additionally received methylprednisolone and her proteinuria decreased. This long-term observation indicates the efficacy of corticosteroids and renin-angiotensin-aldosterone system blockers in the treatment of proteinuria in patients with FLD. The results suggest the role of inflammatory processes as well as dyslipidemia in the pathogenesis of glomerular disorders in LCAT-deficient patients.