Małgorzata Waluś-Miarka

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 < 2.2 × 10(-16)). Modeling in individuals with a 6-SNP score in the top three-fourths of the score distribution indicated a >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.

Carotid Plaques Correlates in Patients With Familial Hypercholesterolemia.

Patients with familial hypercholesterolemia (FH) are at increased risk of premature cardiovascular disease. We compared factors associated with the presence of carotid plaques and carotid intima–media thickness (cIMT), markers of subclinical atherosclerosis, in 241 patients with FH (98, 40.7% men; mean age 41 ± 18.4 years). Patients with FH having carotid plaques (36.5%) had mean age, apolipoprotein (apo) B, glucose, apoA1, systolic blood pressure (SBP) and diastolic BP, waist/hip ratio (WHR), and body mass index higher than patients without plaques. Logistic regression revealed that apoB (odds ratio [OR] per 1 unit change 1.03, P = .005), high-density lipoprotein cholesterol (HDL-C; OR per 1 standard deviation [SD] change 0.59, P = .015), and non-HDL-C (OR per 1SD change 1.53, P = .04) were significantly associated with the presence of plaques. The cIMT correlated with obesity parameters, BP, apoB, glucose, high-sensitivity C-reactive protein, creatinine, γ-glutamyl transpeptidase, and alanine transaminase (P < .001). Regression analysis revealed that cIMT was significantly associated with apoB, SBP, and WHR. These results confirm the role of apoB-containing lipoproteins and low HDL-C with the presence of carotid plaques and apoB, BP, and WHR with cIMT.

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.

Carotid artery plaques – are risk factors the same in men and women with familial hypercholesterolemia?

BACKGROUND AND AIMS High low-density lipoprotein (LDL)-cholesterol levels are a major cause of premature coronary heart disease (CHD) and death in patients with familial hypercholesterolemia (FH). It is uncertain whether these risk factors affect men and women equally. We aimed to compare the risk factors of carotid plaques, which are reliable surrogates of coronary atherosclerosis, in men and women with FH. METHODS 154 patients with FH (40.9% men) were included, diagnosed according to Simon Broome criteria. Carotid plaques were assessed by ultrasound. RESULTS In women multiple logistic regression analysis revealed that systolic blood pressure, high-density lipoprotein-cholesterol (HDL-C), apolipoprotein (apo) A1, and alanine aminotransferase (ALT) were associated with the presence of carotid plaques. In this female cohort, the age adjusted odds ratio for the increase of HDL-C by 1 standard deviation was related to a 55% decrease in the odds of having carotid plaques (p=0.01) and the age adjusted odds ratio for the increase of ALT by 1U/L was related to a 7% in the increase odds of having carotid plaques (p=0.02). In men, in multiple logistic regression analysis only apo B concentration was significantly related to carotid plaque presence. The odds ratio for the increase of apo B by 1mg/dl corresponded to a 4% increase in the odds of having carotid plaques (p=0.01) and, interestingly, in men not treated with statin, this ratio reached 8% (p=0.04). CONCLUSIONS In summary, our study suggests a difference in risk factors of carotid artery plaques between men and women with FH.