Chinese Familial Hypercholesterolemia Clinical Series

Background:Familial hypercholesterolemia(FH)is a monogenic autosomal dominant disorder,which is characterized by extremely elevated low-density lipoprotein cholesterol(LDL-C)levels and higher premature coronary artery disease(CAD)risk.Currently,the most common pathogenic genes are low-density lipoprotein receptor(LDLR),apolipoprotein B(APOB),and proprotein convertase subtilisin/kexin type 9(PCSK9).Although FH increases the global health burden,the diagnosis rate of FH is less than 1%worldwide.The recent published Expert Panel suggested that genetic testing is the "gold standard" for FH diagnosis and expand panels could be performed to improve the diagnostic rate.Besides,early diagnosis and intervention should be performed for FH patients.Although there are some articles explored the genetic mutations in FH patients worldwide,the study evaluating the FH-related genes in patients with very early-onset CAD is currently lacking.Therefore,this study aimed to evaluate the proportion,clinical and genetic mutation characteristics of FH patients in the very early-onset CAD(?35 years)population in China.Methods:A total of 151 patients with age?35 years and LDL-C? 3.4 mmol/L were consecutively enrolled.All patients tested for 9 FH-related genes(LDLR,APOB,PCSK9,APOE,STAP1,LIPA,LDLRAP1,ABCG5/8)by next generation sequencing(NGS).Bioinformatics and function prediction tools were performed to define their pathogenicity.Beside,all the novel pathogenic variants were confirmed by Sanger sequencing.Dutch Lipid Clinic Network(DLCN)and Simon Broome(SB)criteria for FH were also performed.Results:The prevalence of genetically confirmed FH was 38.1%(N=40)in 105 patients including 15 in the LDLR gene,7 in APOB gene,2 in PCSK9 gene,1 in STAP1 gene,4 in homozygous LDLR and 11 in compound genes.FH variant carriers,especially homozygote,had significantly higher plasma LDL-C levels.DLCN categorized 28(26.7%)patients to be probable and definite FH while SB identified 18(17.1%)of patients with possible to be definite FH.Of the 40 patients with pathogenic mutations in FH-related genes,25(62.5%)patients with pathogenic mutations were undiagnosed according to DLCN criteria and 17(42.5%)patients were diagnosed as non-FH according SB criteria.In this study,the best LDL-C threshold value for genetically confirmed FH was 4.56 mmol/L.Conclusions:The present study showed that FH is really a common cause for very early-onset CAD patients(?35 years)with a 38.1%of causative mutations in China and best LDL-C threshold value for predicting pathogenic mutations was 4.56 mmol/L.The under-diagnostic rate of clinical criteria was around 42.5%-62.5%,suggesting that the expanded genetic testing could indeed promote the diagnosis of FH.Background:Arteriosclerotic cardiovascular disease(ASCVD)is one of the most important diseases which is a global health burden currently.The main pathological mechanism of ASCVD is the formation of atherosclerotic plaques in the systemic arteries caused by plasma lipid deposition,which is divided into coronary artery disease(CAD)and peripheral arterial disorder(PAD)according to the affected arteries sites.Proprotein convertase substilisin/kexin type 9(PCSK9)has been proven to be one of the important proteins involved in the regulation of cholesterol metabolism.More and more studies indicated that PCSK9 related to the occurrence and development of CAD in the general population.Lipoprotein(a)[Lp(a)]is a special large molecular lipoprotein particles which is similar to low-density lipoprotein cholesterol(LDL-C).Lp(a)has become one of the research hotspots in the field of cardiovascular and lipids research fields recently.Familial hypercholesterolemia(FH)is one of the common hereditary hyperlipidemias,which is characterized by extremely elevated plasma LDL-C and early-onset CAD.Previous studies have found that plasma PCSK9 and Lp(a)in FH patients are elevated in FH patients compared with the general population,and they are closely related to plasma LDL-C levels.The relationship between plasma PCSK9 and Lp(a)levels and ASCVD has been widely studied in the general population,however,their relationship with ASCVD and the atherosclerotic lesions in different sites in FH patients have not been reported.Thus,this study aimed to analysis whether plasma PCSK9 and Lp(a)levels can be performed as risk factors for ASCVD in FH patients,and their different relationship with different atherosclerotic plaques.Methods:Patients were consecutively enrolled and diagnosed by Dutch Lipid Clinic Network(DLCN)criteria.Patients tested for 9 FH-related genes(LDLR,APOB,PCSK9,APOE,STAP1,LIPA,LDLRAP1,ABCG5/8)by next generation sequencing(NGS).Heterozygous FH(HeFH)patients with a total DLCN score greater than 6 were included in the study.Coronary angiography,carotid color Doppler ultrasound,and lower limb arterial color Doppler ultrasound were used to examine atherosclerotic plaques in the vessels.Coronary and carotid severity was evaluated by Gensini score and Crouse score.Lp(a)and PCSK9 concentrations were determined by and immunoturbidimetry and ELISA,respectively.Finally,the correlations of PCSK9 and Lp(a)with the existence and severity of CAD and peripheral artery disease(PAD)were assessed.Results:One hundred and fifty-one patients with heterozygous FH(HeFH)were enrolled(mean age:47.2;male:58.3%).The distributions of PCSK9 and Lp(a)were skewed and a correlation between them in HeFH patients were found.There were available data regarding coronary angiography and carotid ultrasonography in 151 patients and femoral ultrasonography in 55 patients.PCSK9 levels were significantly higher in patients with coronary and carotid atherosclerotic lesions compared to their non-atherosclerotic groups,while no difference was found in lower limb arterialatherosclerotic lesions groups.Lp(a)levels only differed between patients with or without coronary atherosclerotic lesions.Patients with highest PCSK9 and Lp(a)concentrations had the highest prevalence and severity of atherosclerotic lesions.Multivariate regression analysis showed that PCSK9 was independently associated with CAD and PAD,while Lp(a)was only associated with CAD.Conclusions:The present study demonstrated that elevated plasma PCSK9 was positively associated with CAD and PAD,while Lp(a)only showed an association with CAD in HeFH,which underlined the site specificity for atherosclerotic lesions,suggesting that PCSK9 may be better marker for predicting ASCVD in patients with HeFH compared to Lp(a).Background:Familial hypercholesterolemia(FH)is one of the common hereditary hyperlipidemias,which is characterized by extremely elevated plasma low-density lipoprotein cholesterol(LDL-C)and early-onset coronary artery disease(CAD).Untreated FH patients have a significantly increased risk of major cardiovascular events(MACEs),especially for homozygous FH whose life expectancy is usually less than 30 years by comparison to the general population.Proprotein convertase substilisin/kexin type 9(PCSK9)has been proven to be one of the important proteins involved in the regulation of cholesterol metabolism and been considered as one of the pathogenic genes.The relationship between plasma PCSK9 levels and CAD has been widely studied in the general population.More and more studies have reported that PCSK9 is related to the occurrence and development of atherosclerosis(AS)and can be one of the targets for CAD treatment.In addition,plasma PCSK9 levels have also been found to be predictors of MACEs in the general population.Recent studies have found that the concentration of plasma PCSK9 in patients with FH is much higher than that in the general population,and plasma PCSK9 levels are related to the severity of clinical phenotype of FH.Considering that the high risk and severity of MACEs in FH patients,it is critical to find the potential risk predictors and early identify high-risk groups of patients to initiate diagnosis and treatment as early as possible to accelerate the prognosis of FH patients.However,no data is available on the association between PCSK9 levels and MACEs in FH patients with standard lipid lowering treatment.Therefore,this study aimed to evlauate whether plasma PCSK9 could be served as a risk predictor for future MACEs in FH patients.Methods:Patients were consecutively enrolled and diagnosed by Dutch Lipid Clinic Network(DCN)criteria.Patients tested for 9 FH-related genes(LDLR,APOB,PCSK9,APOE,STAP1,LIPA,LDLRAP1,ABCG5/8)by next generation sequencing(NGS).Heterozygous FH(HeFH)patients with a total DLCN score greater than 6 were included in the study.Multidetector CT and coronary angiography were performed to determine the servity of calcification and AS plaques by coronary artery calcification score(CACS)and Gensini score.Plasma PCSK9 concentrations were determined by enzyme linked immunosorbent assay.Multivariate linear regression analysis was used to calculate the correlation between plasma PCSK9 levels and CACS and Gensini score.Multivariable Cox regression analyses were used to calculate hazard ratios(HR)with 95%confidence intervals(CI).Results:A total of three hundred and thirty-eight patients with HeFH were enrolled(mean age:49.4±11.4;male:58.6%).Multivariate linear regression test showed an independently positive correlation between plasma PCSK9 levels and CACS((?=0.449,p<0.001)and Gensini score((?=0.435,p=0.014).During a mean follow-up of 3 years,33(9.8%)events occurred.Patients with MACEs had higher median PCSK9 levels compared with those without[332.47(294.74-448.96)vs.311.89(246.73-386.61),p=0.038].Plasma PCSK9 levels were arranged in ascending order and separated into tertiles.Kaplan-Meier test revealed that patients with higher PCSK9 presented lower event-free survival(Log-Rank p=0.0017).PCSK9 was statistically associated with MACE after adjusting for confounding factors,with the HR being 3.70(1.16-11.82)for the third tertile compared with the first tertile.When PCSK9 levels were analyzed as continuous variables,we also observed an independent and positive association between PCSK9-per standard deviation and MACEs(HR:1.86;95CI%:1.31-2.65).A Cox prediction model was established based on traditional risk prediction factors.Adding PCSK9 to the Cox prediction model led to a statistical improvement in net reclassification and integrated discrimination.Conclusion:The present study demonstrated that plasma PCSK9 levels were positively associated with the CACS and Gensini score.More importantly,high PCSK9 was found to be positively associated with future adverse cardiovascular outcomes in HeFH patients with standard lipid-lowering therapy,indicating that that measurement of PCSK9 concentration might be useful for cardiovascular risk stratification.