Half a Century Tales of Familial Hypercholesterolemia (FH) in Japan

Is Family History for the Management of Cardiovascular Health in Youth Still Relevant in Clinical Practice?

PURPOSE OF REVIEW

Family history of premature cardiovascular disease is a strong predictor of individual cardiovascular risk. However, family history is not always available and not always reliable. Roughly 80% of health outcomes are influenced not by genetic risk but by societal factors, including adverse health behaviors and environment. Furthermore, in the present age of genetic testing, laboratory evaluations, and imaging, a key question remains: What is the contemporary relevance of family history screening in the management of cardiovascular disease in youth?

RECENT FINDINGS

Knowledge of an individual's family history can help clinicians identify not only inherited risk but also familial clustering of unhealthy behaviors and environmental adversity contributing to enhanced cardiovascular disease risk in youth. For those at greatest risk, prevention strategies can be applied sooner and more conservatively. Integrating family history into clinical practice is crucial for cardiovascular risk assessment and for optimizing outcomes, but, in some cases, is more reflective of social factors.

Validation of physical examinations of tendon xanthomas and changes in the cutoff values of Achilles tendon thickness on radiography in the clinical criteria of heterozygous familial hypercholesterolemia in Japan

BACKGROUND

The 2022 Japan Atherosclerosis Society familial hypercholesterolemia (FH) clinical criteria were modified. In particular, the cutoff value of Achilles tendon thickness (ATT) on radiography was changed from ≥9 mm in both sexes to ≥8.0 mm in men and ≥7.5 mm in women.

METHODS

A total of 872 patients with FH were retrospectively reviewed. Patients were categorized by an ATT of <7.5/8.0 mm (group 1), ≥7.5/8.0 and <9.0 mm (group 2, new group with FH by ATT), and ≥9 mm (group 3).

RESULTS

In total, 492 patients fell into in group 1, 102 in group 2, and 263 in group 3, and 14.0%, 55.9%, and 79.8% of patients in groups 1, 2, and 3, respectively, were positive for a FH mutation. Further, among patients with an LDL cholesterol >180 mg/dL, 37.3%, 77.3%, and 86.5% of patients had a FH mutation in groups 1, 2, and 3, respectively. The proportion of patients with protein-truncating mutation (3.8%, 16.7%, and 53.2%, respectively) differed significantly across groups 1 through 3, respectively. Interestingly, only a very small proportion of the patients in groups 2 and 3 had palpable xanthomas (3.0% and 14.4% respectively).

CONCLUSIONS

This study validates the new radiographic ATT criteria, since the vast majority of patients in the intermediate ATT category had true FH, as shown by positive genetic testing, whereas the old ATT criteria left them with just a deferred diagnosis of FH. In addition, use of physical examination alone for the presence of tendon xanthoma may lead to underdiagnosis of FH.

Impact of changes in Achilles tendon thickening on cardiovascular events in patients with familial hypercholesterolemia

Background

Achilles tendon thickening (ATT) can be ameliorated by lowering low-density lipoprotein (LDL) levels in patients with familial hypercholesterolemia (FH). The Japan Atherosclerosis Society (JAS) defines ATT as ≥8.0 mm in males and ≥7.5 mm in females. We aimed to determine the clinical impact of changes in ATT on the development of major adverse cardiovascular events (MACE).

Methods

Patients with clinically diagnosed heterozygous FH (HeFH) (N = 1273; 614 males, 659 females) with ATT data from X-ray were assessed. Patients were divided into four groups: patients without ATT from baseline until follow-up (group 1), patients without ATT at baseline but developed ATT at follow-up (group 2), patients with ATT at baseline but regressed at follow-up (group 3), and patients with ATT from baseline until follow-up (group 4). Cox proportional hazard models were used to assess the factors associated with MACE, including cardiovascular death and any coronary events.

Results

On follow-up (median: 10.9 years), 142 MACEs were observed, and the median ATT regressed from 7.8 to 7.6 mm. Changes in ATT were significantly associated with the occurrence of MACE in all groups, when compared to group 1 (hazard ratio [HR]: 2.73; 95 % confidence interval [CI]: 1.33-4.13 [p < 0.001], HR: 2.18, 95 % CI: 1.08-3.28, [p < 0.001], HR: 6.34, 95 % CI: 3.10-9.58, [p < 0.001], in groups 2, 3, and 4, respectively).

Conclusions

Assessing ATT has diagnostic value and allows for risk stratification among patients with HeFH.

Validation of the 2022 Clinical Diagnostic Criteria of Familial Hypercholesterolemia in Japan

AIM

In 2022, the Japan Atherosclerosis Society (JAS) has revised its clinical diagnostic criteria of familial hypercholesterolemia (FH) and adopted the use of definite, probable, possible, and unlikely FH according to the Dutch Lipid Clinic Network (DLCN) FH criteria. However, these strata have not been validated and their impact on coronary artery disease (CAD) is yet to be elucidated.

METHODS

In this study, we retrospectively examined the patients with FH aged ≥ 15 years (N=857, male=431) who were admitted to Kanazawa University Hospital between 2010 and 2022. We assessed the prevalence of patients with a pathogenic variant as FH and odds ratio (OR) of CAD among each group determined by the JAS criteria 2022 for adults.

RESULTS

In total, 414, 128, 142, and 173 patients were found to have definite, probable, possible, and unlikely FH, respectively, in this population. The prevalences of patients with a pathogenic variant as FH were 77.1%, 28.7%, 13.0%, and 1.2 %, respectively, among the definite, probable, possible, and unlikely FH patients (P-trend ＜0.001). Compared with the reference group of unlikely FH, patients with definite, probable, and possible FH were noted to have significantly higher adjusted odds of developing CAD (OR, 9.1; 95% confidence interval [CI], 3.2-12.6; P＜0.001 and OR, 4.2; 95% CI, 1.7-6.4; P＜0.001, and OR, 2.8; 95% CI, 1.2-4.4; P=0.002, respectively).

CONCLUSION

The new JAS diagnostic criteria for FH have been noted to work well in terms of diagnosing definitive, probable, or possible FH patients. Thus, it is seen to be of great help in terms of risk discrimination.

Familial hypercholesterolemia with special focus on Japan

Familial hypercholesterolemia (FH) is an inherited disorder characterized by increased low-density lipoprotein LDL) cholesterol and atherosclerotic cardiovascular disease. Although initial genetic analysis linked FH to LDL receptor mutations, subsequent work demonstrated that a gain-of-function mutation in the proprotein convertase subtilisin/kexin type 9 (PCSK9), which causes LDL-R degradation, was shown to be the cause of FH. In this review, we describe the history of research on FH, its clinical phenotyping and genotyping and advances in treatment with special focus on Japan.

Genetic Counseling and Genetic Testing for Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is one of the most common autosomal codominant Mendelian diseases. The major complications of FH include tendon and cutaneous xanthomas and coronary artery disease (CAD) associated with a substantial elevation of serum low-density lipoprotein levels (LDL). Genetic counseling and genetic testing for FH is useful for its diagnosis, risk stratification, and motivation for further LDL-lowering treatments. In this study, we summarize the epidemiology of FH based on numerous genetic studies, including its pathogenic variants, genotype-phenotype correlation, prognostic factors, screening, and usefulness of genetic counseling and genetic testing. Due to the variety of treatments available for this common Mendelian disease, genetic counseling and genetic testing for FH should be implemented in daily clinical practice.

Familial hypercholesterolemia is related to cardiovascular disease, heart failure and atrial fibrillation. Results from a population-based study

BACKGROUND

Familial hypercholesterolemia (FH) is associated with atherosclerotic cardiovascular disease (ASCVD). However, the prevalence of FH among a general population remains unknown, and it is unclear if FH is associated with other cardiovascular complications, including heart failure (HF) and atrial fibrillation (AF).

METHODS

Analyses were conducted on individuals without a prior history of cardiovascular disease using a nationwide health claims database collected in the JMDC Claims Database between 2005 and 2022 (n = 4,126,642; median age, 44 years; 57.5% men). We defined FH as either LDL cholesterol ≥250 mg/dL or LDL cholesterol ≥175 mg/dL under the lipid-lowering medications under the assumption that lipid-lowering medications reduced LDL cholesterol by 30%. We assessed the associations between FH and composite outcomes, including, ASCVD (myocardial infarction, angina pectoris, and stroke), HF, and AF using Cox proportional hazard model.

RESULTS

We identified 11,983 (.29%) FH patients. In total, 181,150 events were recorded during the mean follow-up period of 3.5 years. The status FH was significantly associated with composite outcomes after adjustments (hazard ratio [HR]; 1.38, 95% confidence interval [CI]: 1.30-1.47, p < .001). Interestingly, the status FH was significantly associated with HF (HR: 1.48, 95% CI: 1.36-1.61, p < .001) and AF (HR: 1.33, 95% CI: 1.08-1.64, p < .001) in addition to angina pectoris (HR: 1.45, 95% CI: 1.33-1.58, p < .001) and stroke (HR: 1.19, 95% CI: 1.04-1.36, p < .001).

CONCLUSION

We found that the prevalence of FH was .29% in a general population. FH was significantly associated with a higher risk of developing cardiovascular disease, HF and AF.

LAY SUMMARY

We sought to identify the prevalence of FH among a general population, and to clarify whether FH increases the risk of not only ASCVD but also HF and AF.

Impact of the severe familial hypercholesterolemia status on atherosclerotic risks

Risks of atherosclerotic events substantially vary even among patients with familial hypercholesterolemia (FH) with extremely high risk based on life-long exposure to high low-density lipoprotein cholesterol levels. This study aimed to examine the impact of the severe FH status defined by the International Atherosclerosis Society (IAS). Data of patients with FH (N = 1050, male = 490) who were admitted to Kanazawa University Hospital between 2000 and 2020 and who were followed up were retrospectively reviewed. The number of major adverse cardiac events (MACEs), including mortality associated with cardiovascular disease, acute coronary syndrome, and ischemic heart disease requiring coronary revascularization per 1000 person-years, was calculated. Hazard ratio was also calculated using Cox proportional model. Overall, 545 (51.9%) patients had severe FH. The median follow-up duration was 12.6 years. In total, 171 MACEs were recorded during the follow-up period. Severe FH was significantly associated with MACE (hazard ratio = 6.48, 95% confidence interval = 2.56-10.40, P = 1.2 × 10-5). The event rates per 1000 person-years in the primary prevention group of non-severe FH and severe FH, were 0.0 and 15.6, respectively. The event rates per 1000 person-years in the secondary prevention group of non-severe FH and severe FH, were 2.0 and 32.3, respectively. Patients with severe FH exhibited significantly higher risks in primary and secondary prevention settings. This simple criterion provides useful information for identifying patients with even higher risk who may need further management.

Coronary Artery and Carotid Artery Plaques in Patients With Heterozygous Familial Hypercholesterolemia

Background

Little is known regarding the formation of coronary and carotid plaques and their impact on cardiovascular disease in patients with familial hypercholesterolemia (FH).

Objectives

This study aimed to determine: 1) if the development of coronary and carotid plaques is correlated; and 2) if these plaques are associated with major adverse cardiac events (MACEs) defined as cardiovascular-related death, unstable angina, myocardial infarction, or staged revascularization.

Methods

This was a retrospective review of 622 patients with heterozygous FH (HeFH) at Kanazawa University Hospital, assessed coronary and carotid plaque scores using coronary computed tomography and carotid ultrasound within 1 year. Spearman correlation coefficients were assessed among variables. Risk factors for MACEs were determined using the Cox proportional hazard model.

Results

Coronary and carotid plaque scores were significantly correlated in patients with HeFH in both sexes (Spearman's r = 0.82; P < 0.001 in males and Spearman's r = 0.87; P < 0.001 in females). We observed 132 MACEs during the median follow-up of 13.2 years. These scores were significantly associated with the occurrence of MACE (HR: 3.33; 95% CI: 1.88-4.78; P < 0.001, HR: 2.24; 95% CI: 1.28-3.20; P < 0.001, respectively).

Conclusions

Coronary and carotid plaque scores were significantly correlated, and both were independently associated with MACEs. The assessments for coronary and/or carotid plaque are useful for further risk stratifications in patients with HeFH.

Cholesterol Screening in Children: Is a Universal Approach Working?

PURPOSE OF REVIEW

Ample evidence supports that an individual's lifetime risk of atherosclerotic cardiovascular disease correlates to long-term, cumulative exposure to circulating cholesterol levels, beginning in childhood. Selective screening strategies based on family history fail to identify many children with hypercholesterolemia. Universal cholesterol screening in childhood is a worthwhile goal. However, cholesterol screening rates through childhood remain low.

RECENT FINDINGS

Mounting evidence clarifies the barriers to cholesterol screening in children. Specific strategies to foster universal screening in childhood have been proposed.

SUMMARY

We present an overview of the present state of childhood cholesterol screening, summarizing historical and contemporary guidelines and collating evidence of low adherence to current guidelines. We contend that novel approaches to universal cholesterol screening in childhood are warranted, and we present potential opportunities for improvement. We call for new and universal pediatric cholesterol screening guidelines.

Guidelines for the Diagnosis and Treatment of Pediatric Familial Hypercholesterolemia 2022

As atherosclerosis begins in childhood, early diagnosis and treatment of familial hypercholesterolemia (FH) is considered necessary. The basic diagnosis of pediatric FH (under 15 years of age) is based on hyper-low-density lipoprotein (LDL) cholesterolemia and a family history of FH; however, in this guideline, to reduce overlooked cases, "probable FH" was established. Once diagnosed with FH or probable FH, efforts should be made to promptly provide lifestyle guidance, including diet. It is also important to conduct an intrafamilial survey, to identify family members with the same condition. If the level of LDL-C remains above 180 mg/dL, drug therapy should be considered at the age of 10. The first-line drug should be statin. Evaluation of atherosclerosis should be started using non-invasive techniques, such as ultrasound. The management target level is an LDL-C level of less than 140 mg/dL. If a homozygous FH is suspected, consult a specialist and determine the response to pharmacotherapy with evaluating atherosclerosis. If the response is inadequate, initiate lipoprotein apheresis as soon as possible.

Coronary artery calcium among patients with heterozygous familial hypercholesterolaemia

Aims

We aimed to determine if coronary artery calcium (CAC) is associated with cardiovascular disease (CVD) events, defined as CVD-related death, unstable angina, myocardial infarction, or staged revascularization among patients with heterozygous familial hypercholesterolaemia (HeFH) under primary prevention settings.

Methods and results

Data of patients with FH admitted to Kanazawa University Hospital between 2000 and 2020, who underwent CAC measurement and were followed up (n = 622, male = 306, mean age = 54 years), were retrospectively reviewed. Risk factors for CVD events were determined using the Cox proportional hazard model. The median follow-up duration was 13.2 years (interquartile range: 9.8-18.4 years). We observed 132 CVD events during the follow-up period. The event rate per 1000 person-years for CAC scores of 0 [n = 283 (45.5%)], 1-100 [n = 260 (41.8%)], and >100 [n = 79 (12.7%)] was 1.2, 17.0, and 78.8, respectively. Log (CAC score + 1) was a significant predictor of the occurrence of CVD events (hazard ratio: 3.24; 95% confidence interval: 1.68-4.80; P < 0.0001) in the multivariate Cox regression analysis, independent of other factors. The risk discrimination of CVD events was enhanced by adding CAC information to other conventional risk factors (C-statistics: 0.833-0.934; P < 0.0001).

Conclusion

The CAC score helps in further risk stratification in patients with HeFH.

Attainment of the low-density lipoprotein cholesterol treatment target and prognosis of heterozygous familial hypercholesterolemia

BACKGROUND AND AIMS

No previous study has investigated the association between attainment of low-density lipoprotein (LDL) cholesterol treatment target and better prognosis in patients with familial hypercholesterolemia (FH). The current research aimed to examine the association between attainment of LDL cholesterol treatment target and major adverse cardiac events (MACEs) in patients with FH to validate the current LDL cholesterol treatment targets in primary (<100 mg/dL) and secondary (<70 mg/dL) prevention settings.

METHODS

The data of patients with FH who were admitted to Kanazawa University Hospital between 2000 and 2020 and who were followed-up were retrospectively reviewed. The number of MACEs, including mortality associated with cardiovascular disease, unstable angina, and myocardial infarction per 1000 person-years, was calculated for each stratum for the attainment of LDL cholesterol target.

RESULTS

The median follow-up duration was 12.6 years. In total, 132 MACEs were recorded during the follow-up period. The numbers of patients who attained the LDL cholesterol target in the primary and secondary prevention groups were 228 (31.9%) and 40 (11.9%), respectively. The event rates per 1000 person-years for LDL cholesterol levels of <100 and ≥100 mg/dL in the primary prevention group were 2.6 and 4.4, respectively. The event rates per 1000 person-years for LDL cholesterol levels of <70 and ≥70 mg/dL in the secondary prevention group were 15.3 and 27.5, respectively.

CONCLUSIONS

Attainment of the LDL cholesterol target is associated with better prognosis in patients with FH. However, the attainment rate is currently inadequate among Japanese.

Impact of Healthy Lifestyle in Patients With Familial Hypercholesterolemia

Background

Pathogenic mutations are associated with poor outcomes in patients with familial hypercholesterolemia (FH). However, data on the effects of a healthy lifestyle on FH phenotypes are limited.

Objectives

The authors investigated the interaction between a healthy lifestyle and FH mutation with prognosis in patients with FH.

Methods

We investigated the associations of the interaction between genotypes and lifestyle, with the occurrence of major adverse cardiac events (MACE), such as cardiovascular-related mortality, myocardial infarction, unstable angina, and coronary artery revascularization, in patients with FH. We assessed their lifestyle based on 4 questionnaires (healthy dietary pattern, regular exercise, not smoking, and absence of obesity). The Cox proportional hazards model was used to assess the risk for MACE.

Results

The median follow-up duration was 12.6 (IQR: 9.5-17.9) years. During the follow-up duration, 179 MACE were observed. Independent of classic risk factors, FH mutation and lifestyle score were significantly associated with MACE (HR: 2.73; 95% CI: 1.03-4.43; P = 0.02; and HR: 0.69, 95% CI: 0.40-0.98, P = 0.033, respectively). The estimated risk of coronary artery disease by 75 years of age varied according to lifestyle, ranging from 21.0% among noncarriers with a favorable lifestyle to 32.1% among noncarriers with an unfavorable lifestyle and ranging from 29.0% among carriers with a favorable lifestyle to 55.4% among carriers with an unfavorable lifestyle.

Conclusions

A healthy lifestyle was associated with reduced risk for MACE among patients with FH with or without genetic diagnosis.

Synergistic effect of lipoprotein (a) and C-reactive protein on prognosis of familial hypercholesterolemia

•

Lp(a) levels among patients with pathogenic variant FH were significantly elevated.

•

Lp(a) and CRP levels were not associated with MACE by themselves.

•

Lp(a) level was significantly associated with MACE only when the CRP level was elevated.

Objective

The synergistic effect of lipoprotein (a) [Lp(a)] and C-reactive protein (CRP) on major adverse cardiovascular events (MACE) among patients with familial hypercholesterolemia (FH) is unknown. This study aimed to investigate the relations between Lp(a) and CRP levels and MACE in patients with FH whose Lp(a) levels are elevated.

Methods

We retrospectively investigated associations between genotypes and phenotypes, including low-density lipoprotein (LDL) cholesterol level and the occurrence of MACE among patients with FH (N = 786, male/female: 374/412). A Cox proportional hazard model was used to identify factors associated with MACE, adjusting for traditional risk factors. Patients with FH were divided into four groups, based on their Lp(a) and CRP levels, and assessed using Kaplan–Meier curves.

Results

The median follow-up was 12.6 years (interquartile range [IQR], 9.5–17.9 years). During follow-up, 129 MACE were observed. Median Lp(a) and CRP levels were 21.4 (10.9–38.3) mg/dL and 0.20 (0.11–0.29) mg/dL, respectively. Under these conditions, natural log-transformed Lp(a) and CRP were not associated with MACE (hazard ratio [HR], 1.08; 95% confidence interval [CI], 0.91–1.25; P = 0.220; and HR, 1.12; CI, 0.96–1.28; P = 0.190, respectively). However, in Group 4, Lp(a) and CRP were significantly associated with MACE (HR, 2.44; CI, 1.42–3.46; P = 1.8 × 10⁻⁷).

Conclusions

In patients with FH, Lp(a) was significantly associated with MACE only when the CRP level was elevated. Patients with FH whose Lp(a) and CRP levels are elevated should be treated aggressively.

Early Diagnosis and Treatments in Childhood are Associated with Better Prognosis in Patients with Familial Hypercholesterolemia

Objective

The early diagnosis and treatment initiation for children with familial hypercholesterolemia (FH) has been recommended in guidelines. However, there is limited data on the impact of early treatments on the prognosis of children with FH. To investigate if the early initiation of lipid-lowering therapies among Japanese pediatric patients with FH reduced the occurrence of cardiovascular disease (CVD) events in them.

Methods

We retrospectively investigated the occurrence of CVD events (myocardial infarction, unstable angina, or coronary artery revascularization) in patients with FH (N = 1050, male/female = 490/560), including 106 children below 20 years. We compared a variety of phenotypes, including genetic backgrounds, other complications, LDL cholesterol, medical therapies, and their prognoses between the patients’ diagnoses before the age of 20 years (children, mean age = 15 years) and after that age (adults, mean age = 52 years). Overall, 290 patients (27.6%) had a history of prior CVD events.

Results

The median follow-up duration was 12.6 [9.5–17.9] years. The baseline LDL cholesterol level, 239 mg/dL, dropped to 112 mg/dL with the treatments. The Achilles tendon thickness was significantly lower in children than that of adults (7.2 vs. 8.9 mm, P < 0.001). Over the follow-up duration, 119 CVD events were observed. Importantly, no CVD event was observed in children despite their median LDL cholesterol level at follow-up being significantly higher than that of adults (122 vs. 111 mg/dL, P < 0.001).

Conclusion

The likelihood of CVD events in those with FH diagnosed and treated in childhood is low.

Familial Hypercholesterolaemia as a Predisposing Factor for Atherosclerosis

Lipid metabolism alterations are an important component of the pathogenesis of atherosclerosis. However, it is now clear that the atherogenesis process involves more than one mechanism, and more than one condition can predispose this condition. Multiple risk factors contribute to the atherosclerosis initiation and define its course. Familial hypercholesterolaemia is a disorder of lipid metabolism that often leads to atherosclerosis development. As is clear from the disease name, the hallmark is the increased levels of low-density lipoprotein cholesterol (LDL-C) in blood. This creates favourable conditions for atherogenesis. In this review, we briefly described the familial hypercholesterolaemia and summarized data on the relationship between familial hypercholesterolaemia and atherosclerosis.

Case report: Unusual coexistence between familial hypercholesterolemia and familial hypobetalipoproteinemia

Type 1 familial hypobetalipoproteinemia (FHBL1), characterized by low levels of apolipoprotein B (ApoB)-containing lipoproteins, elevation of transaminases, and hepatic steatosis, is a rare disease the prevalence of which is 1 in 3,000 among general population. Here we report an extremely rare family where phenotypes of familial hypercholesterolemia (FH) are canceled by coexistence of FHBL1 caused by an truncating mutation in apolipoprotein B (APOB).

Genetic Analysis of Japanese Children Clinically Diagnosed with Familial Hypercholesterolemia

AIM

This study aimed to elucidate the gene and lipid profiles of children clinically diagnosed with familial hypercholesterolemia (FH).

METHODS

A total of 21 dyslipidemia-related Mendelian genes, including FH causative genes (LDLR, APOB, and PCSK9) and LDL-altering genes (APOE, LDLRAP1, and ABCG5/8), were sequenced in 33 Japanese children (mean age, 9.7±4.2 years) with FH from 29 families.

RESULTS

Fifteen children (45.5%) with pathogenic variants in LDLR (eight different heterozygous variants) and one child (3.0%) with the PCSK9 variant were found. Among 17 patients without FH causative gene variants, 3 children had variants in LDL-altering genes, an APOE variant and two ABCG8 variants. The mean serum total cholesterol (280 vs 246 mg/dL), LDL-cholesterol (LDL-C, 217 vs 177 mg/dL), and non-HDL cholesterol (228 vs 188 mg/dL) levels were significantly higher in the pathogenic variant-positive group than in the variant-negative group. In the variant-positive group, 81.3% of patients had LDL-C levels ≥ 180 mg/dL but 35.3% in the variant-negative group. The mean LDL-C level was significantly lower in children with missense variants, especially with the p.Leu568Val variant, than in children with other variants in LDLR, whereas the LDL-altering variants had similar effects on the increase in serum LDL-C to LDLR p.Leu568Val.

CONCLUSION

Approximately half of the children clinically diagnosed with FH had pathogenic variants in FH causative genes. The serum LDL-C levels tend to be high in FH children with pathogenic variations, and the levels are by the types of variants. Genetic analysis is useful; however, further study on FH without any variants is required.

Effects of Different Types of Pathogenic Variants on Phenotypes of Familial Hypercholesterolemia

Objective: It has been shown that pathogenic variants are associated with poor clinical outcomes in patients with familial hypercholesterolemia (FH). However, data on the effect of different types of pathogenic variants on FH phenotype is limited.

Methods: We retrospectively investigated the associations between genotypes and phenotypes, including low-density lipoprotein (LDL) cholesterol level and the occurrence of major adverse cardiac events (MACEs), defined as cardiovascular death, myocardial infarction, unstable angina, or coronary artery revascularization, in patients with FH (N = 1,050, male/female = 490/560). Based on genotype, the patients were divided into the following three groups: patients without pathogenic variants, patients with missense variants, and patients with protein-truncating variants (PTVs). Cox proportional hazard model was used to identify the factors associated with MACEs.

Results: The median follow-up duration was 12.6 years (interquartile range = 9.5–17.9 years). There were 665 patients with FH-mutation (277 patients with missense variants and 388 patients with PTVs) and 385 patients without FH-mutation. Over the follow-up duration, 175 MACEs were observed. We identified 89 different pathogenic variants in the 665 patients with FH. LDL cholesterol level was found to be significantly higher in patients with PTVs (256 mg/dl) than in patients with missense variants (236 mg/dl) and patients without pathogenic variants (216 mg/dl). It was also found that PTVs and missense variants are significantly associated with MACEs (hazard ratio [HR] = 1.58, 95% confidence interval [CI] = 1.08–2.08, p = 0.0033 and HR = 3.24, 95% CI = 2.12–4.40, p = 3.9 × 10⁻⁶, respectively), independent of classical risk factors.

Conclusion: Pathogenic variants, especially PTVs, are significantly associated with poor outcomes in patients with FH. Genetic testing is useful for the diagnosis and risk stratification of patients with FH.

Individualized Treatment for Patients With Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is one of the most common and, therefore, important inherited disorders in preventive cardiology. This disease is mainly caused by a single pathogenic mutation in the low-density lipoprotein receptor or its associated genes. Moreover, it is correlated with a high risk of cardiovascular disease. However, the phenotype severity even in this monogenic disease significantly varies. Thus, the current study aimed to describe FH and its importance and the factors (inherited and acquired) contributing to differences in phenotype severity. Different lipid-modification therapies according to these factors can lead to individualized treatments, which are also essential in the general populations.

The Assessment of Carotid Atherosclerotic Plaque among Young Patients with Familial Hypercholesterolemia

Objective Few data exist regarding when atherosclerotic changes occur among patients with familial hypercholesterolemia (FH). Carotid ultrasonography is a non-invasive method of evaluating this issue. The present study (1) compared the clinical utilities of carotid intima-media thickness (cIMT) and carotid plaque score (cPS) and (2) estimated the onset and progression of carotid atherosclerosis among patients with heterozygous FH (HeFH). Methods We retrospectively analyzed 511 patients under 30 years old who underwent carotid ultrasonography at our hospital from 2006 to 2019. We classified them into the HeFH group (n=78, 21.4±5.9 years old) and non-FH group (n=433, 23.4±6.0 years old) based on the clinical diagnosis and compared their cIMT and cPS values. In addition, we estimated the onset and progression of carotid atherosclerosis among young HeFH patients. Results There was no significant difference in the cIMT between the HeFH and non-FH groups (0.44 mm vs. 0.42 mm, p=0.25). In contrast, the cPS was significantly higher in the HeFH group than in the non-FH group (1.11 vs. 0.26, p=0.002). The regression equation for cPS of HeFH group was Y=-2.05+0.15X (r=0.37, p<0.001). Conclusion An assessment based on the cPS rather than the cIMT appears to be better to capture the progress of carotid atherosclerosis among young HeFH patients. Carotid atherosclerosis may start to develop at 14 years old in patients with HeFH.

Personalized medicine in cardiovascular disease: review of literature

Purpose

Personalized medicine (PM) is the concept of managing patients based on their characteristics, including genotypes. In the field of cardiology, advantages of PM could be found in the diagnosis and treatment of several conditions such as arrhythmias and cardiomyopathies; moreover, it may be beneficial to prevent adverse drug reactions (ADR) and select the best medication. Genetic background can help us in selecting effective treatments, appropriate dose requirements, and preventive strategies in individuals with particular genotypes.

Method

In this review, we provide examples of personalized medicine based on human genetics for the most used pharmaceutics in cardiology, including warfarin, clopidogrel, and statins. We also review cardiovascular diseases, including coronary artery disease, arrhythmia, and cardiomyopathies.

Conclusion

Genetic factors are as important as environmental factors and they should be tested and evaluated more in the future by improving in genetic testing tools.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00840-0.

Genetic mutations, regression of Achilles tendon thickness, and cardiovascular events among patients with familial hypercholesterolemia

BACKGROUND AND AIMS

Achilles tendon thickness (ATT) can be regressed through LDL-lowering in patients with familial hypercholesterolemia (FH). We aimed to determine factors associated with regression of ATT and its role in development of major adverse cardiovascular events (MACE).

METHODS

Patients with clinically diagnosed FH (N = 1,050, male/female = 490/560) were retrospectively assessed. FH-related gene mutations and ATT data using X-ray were collected. Multivariable linear regression analysis was exploited to test the factors associated with deterioration of ATT. Cox proportional hazards models were used to assess factors associated with MACE, including cardiovascular death and acute coronary events.

RESULTS

The median follow-up period was 12.6 years. FH-linked mutations were identified in 777 patients. During the follow-up period, 113 MACEs were observed, and median ATT was regressed from 8.7 to 8.5 mm. We found that there was more significant positive correlation between cholesterol-year score and ATT among patients with FH-related gene mutation (p < 2.2 × 10^-16; Spearman's r = 0.42). Multivariable linear regression analyses revealed that age (standardized coefficients [SCs] = 0.307, 95% confidence interval [CI] = 0.241-0.373), hypertension (SCs = 0.069, 95%CI = 0.001-0.138), and diabetes (SCs = 0.059, 95% CI = 0.003-0.115) were positively correlated with changes in ATT (progression). Baseline ATT (SCs = -0.474, 95%CI = -0.535-0.413) and FH-related mutations (SCs = -0.058, 95%CI = -0.091-0.024) were negatively correlated with changes in ATT (regression). Considering this confounding factors, regression of ATT was significantly associated with reduced MACE (hazard ratio [HR] = 0.67, 95%CI = 0.51-0.89, per 1.0 mm).

CONCLUSIONS

Assessed ATT condition and presence of FH-linked gene mutations represent diagnostic values and risk stratification information among patients with FH.

Effects of artificial intelligence-SsupporTed Automated NutRiTional Intervention on LDL cholesterol Control in Patients with Familial Hypercholesterolaemia (iSTART-FH): protocol for a randomised controlled trial

Introduction

Familial hypercholesterolaemia (FH) is an autosomal dominant inherited genetic disease that has an extremely elevated cardiovascular risk because of their significantly elevated low-density lipoprotein (LDL) cholesterol. Nutritional intervention is needed in improving LDL cholesterol control in patients with FH but requires a considerable burden in manpower. Artificial intelligence (AI)-supported and mobile-supported nutritional intervention using this technique may be an alternative approach to traditional nutritional counselling in person. This study aims to test the hypothesis that AI-supported nutritional counselling is more effective in reducing LDL cholesterol than the in-person, face-to-face method in terms of improving LDL cholesterol control in patients with FH.

Methods and analysis

This is a single-centre, unblinded, cross-over, randomised controlled study comparing the efficacy of AI-supported automated nutrition therapy with that of conventional human nutrition counselling in patients with FH. Patients with FH are recruited and randomly assigned to AI-supported nutrition counselling (n=30) and to face-to face nutrition counselling (n=30). We are using an Asken, a mobile application that has been specially modified for this study so that it follows the recommendations by the Japan Atherosclerosis Society. We started patient recruitment on 1 September 2020, and is scheduled to continue until 31 December 2022.

Ethics and dissemination

This study is being conducted in compliance with the Declaration of Helsinki, the Ethical Guidelines for Medical and Health Research Involving Human Subjects, and all other applicable laws and guidelines in Japan. The study protocol was approved by the Institutional Review Board of Kanazawa University on 13 April 2020 (IRB no. 2623-3); all recruited patients are required to provide written informed consent. We will disseminate the final results at international conferences and in a peer-reviewed journal.

Trial registration number

UMIN000040198.

Effect of Cumulative Exposure to Low-Density Lipoprotein-Cholesterol on Cardiovascular Events in Patients With Familial Hypercholesterolemia

BACKGROUND

Recent studies suggest that cumulative exposure to low-density lipoprotein-cholesterol (LDL-C) leads to the development of atherosclerotic cardiovascular disease (ASCVD). However, few studies have investigated whether this link extends to individuals with familial hypercholesterolemia (FH), a relevant patient population.

METHODS AND RESULTS

We retrospectively investigated the health records of 1,050 patients with clinical FH diagnosis between April 1990 and March 2019. We used Cox proportional hazards models adjusted for established ASCVD risk factors to assess the association between cholesterol-year-score and major adverse cardiovascular events (MACEs), including death from any cause or hospitalization due to ASCVD events. Cholesterol-year-score was calculated as LDL-C max × [age at diagnosis/statin initiation] + LDL-C at inclusion × [age at inclusion - age at diagnosis/statin initiation]. The median follow-up period for MACE evaluation was 12.3 (interquartile range, 9.1-17.5) years, and 177 patients experienced MACEs during the observation period. Cholesterol-year-score was significantly associated with MACEs (hazard ratio, 1.35; 95% confidence interval, 1.07-1.53; P=0.0034, per 1,000 mg-year/dL), independent of other traditional risk factors including age and LDL-C, based on cross-sectional assessment. Cholesterol-year-score improved the discrimination ability of other traditional risk factors for ASCVD events (C-index, 0.901 vs. 0.889; P=0.00473).

CONCLUSIONS

Cumulative LDL-C exposure was strongly associated with MACEs in Japanese patients with FH, warranting early diagnosis and treatment initiation in these patients.

Prospective Registry Study of Primary Dyslipidemia (PROLIPID): Rationale and Study Design

Introduction: Primary dyslipidemias are inherited disorders in plasma lipoprotein metabolism that lead to serious cardiovascular and other complications. The Japanese Ministry of Health, Labor and Welfare (MHLW) covers medical expenses, under the Research Program on Rare and Intractable Diseases, for homozygous familial hypercholesterolemia (FH), familial chylomicronemia, sitosterolemia, cerebrotendinous xanthomatosis, lecithin:cholesterol acyltransferase deficiency, Tangier disease, and abetalipoproteinemia. Apolipoprotein A1 deficiency, heterozygous FH, and type III hyperlipoproteinemia are covered by the MHLW Pediatric Chronic Disease Program. Heterozygous FH and type III hyperlipoproteinemia are also important for their relatively common prevalence and, accordingly, high impact on Japanese public health by significant contribution to the overall prevalence of cardiovascular diseases. Therefore, a systemic survey of these diseases is mandatory to estimate their actual situation, such as prevalence, clinical manifestations, and prognoses among the Japanese population. The impact of these rare and intractable diseases on cardiovascular and other complications will likely be higher among Japanese people than other ethnicities because the general Japanese population has many cardioprotective aspects. The current study intends to conduct a multicenter registry of these diseases to assess their demographics and clinical features comprehensively.

Methods and Analysis: The Prospective Registry Study of Primary Dyslipidemia is a registry-based prospective, observational, multicenter cohort study in Japan, enrolling patients who fulfill the Japanese clinical criteria of the primary dyslipidemias listed above, from 26 participating institutes from August 2015 to March 2023. A total of 1,000 patients will be enrolled in the study and followed for 10 years. Clinical parameters are collected, including physical and laboratory findings, genetic analysis, drugs, lifestyle management, and clinical events, especially cardiovascular events. The primary endpoint of this study is the new onset of cardiovascular disease and acute pancreatitis, and the secondary endpoint is death from any causes.

Ethics and Dissemination: This study complies with the Declaration of Helsinki, the Ethical Guidelines for Medical and Health Research Involving Human Subjects, and all other applicable laws and guidelines in Japan. The institutional review boards have approved this study protocol at all participating institutes. The final results are to be published at appropriate international conferences and in peer-reviewed journals.

Familial Hypercholesterolaemia in the Malaysian Community: Prevalence, Under-Detection and Under-Treatment

AIM

Familial hypercholesterolaemia (FH) is the most common autosomal dominant lipid disorder, leading to severe hypercholesterolaemia. Early detection and treatment with lipid-lowering medications may reduce the risk of premature coronary artery disease in FH patients. However, there is scarcity of data on FH prevalence, detection rate, treatment and control with lipid-lowering therapy in the Malaysian community.

METHODS

Community participants (n=5130) were recruited from all states in Malaysia. Blood samples were collected for lipid profiles and glucose analyses. Personal and family medical histories were collected by means of assisted questionnaire. Physical examination for tendon xanthomata and premature corneal arcus were conducted on-site. FH were clinically screened using Dutch Lipid Clinic Network Criteria.

RESULTS

Out of 5130 recruited community participants, 55 patients were clinically categorised as potential (Definite and Probable) FH, making the prevalence FH among the community as 1:100. Based on current total population of Malaysia (32 million), the estimated number of FH patients in Malaysia is 320,000, while the detection rates are estimated as 0.5%. Lipid-lowering medications were prescribed to 54.5% and 30.5% of potential and possible FH patients, respectively, but none of them achieved the therapeutic LDL-c target.

CONCLUSION

Clinically diagnosed FH prevalence in Malaysian population is much higher than most of the populations in the world. At community level, FH patients are clinically under-detected, with majority of them not achieving target LDL-c level for high-risk patients. Therefore, public health measures are warranted for early detection and treatment, to enhance opportunities for premature CAD prevention.

Phenotypic and Genetic Analyses of Korean Patients with Familial Hypercholesterolemia: Results from the KFH Registry 2020

Aims: Familial hypercholesterolemia (FH) is currently a worldwide health issue. Understanding the characteristics of patients is important for proper diagnosis and treatment. This study aimed to analyze the phenotypic and genetic features, including threshold cholesterol levels, of Korean patients with FH.

Methods: A total of 296 patients enrolled in the Korean FH registry were included, according to the following criteria: low-density lipoprotein-cholesterol (LDL-C) ＞190 mg/dL with tendon xanthoma or family history compatible with FH, or LDL-C ＞225 mg/dL. DNA sequences of three FH-associated genes were obtained using whole-exome or target exome sequencing. Threshold cholesterol levels for differentiating patients with FH/pathogenic variant (PV) carriers and predictors of PVs were identified.

Results: Of the 296 patients, 104 had PVs and showed more obvious clinical findings, including higher cholesterol levels. PV rates ranged from 30% to 64% when patients were categorized by possible or definite type according to the Simon Broome criteria. Frequent PV types included missense variants and copy number variations (CNVs), while the most frequent location of PVs was p.P685L inLDLR. The threshold LDL-C levels for patient differentiation and PV prediction were 177 and 225 mg/dL, respectively. Younger age, tendon xanthoma, and higher LDL-C levels were identified as independent predictors of PVs, while traditional cardiovascular risk factors were predictors of coronary artery disease.

Conclusions: Korean patients with FH had variable PV rates depending on diagnostic criteria and distinctive PV locations. The reported threshold LDL-C levels pave the way for efficient patient care in this population.

Achilles Tendon Thickness Assessed by X-ray Predicting a Pathogenic Mutation in Familial Hypercholesterolemia Gene

AIM

The 2017 Japan Atherosclerosis Society (JAS) familial hypercholesterolemia (FH) criteria adopt a cut-off value of ≥ 9 mm of Achilles tendon thickness (ATT) detected by X-ray as one of the three key items. This threshold was determined based on an old data evaluating the ATT of 36 non-FH individuals that was published in 1977. Although the specificity of these clinical criteria is extremely high due to a strict threshold, there are a significant number of patients with FH whose ATT ＜9 mm. We aimed to determine a cut-off value of ATT detected by X-ray to differentiate FH and non-FH based on genetic diagnosis.

METHODS

The individuals (male/female=486/501) with full assessments of genetic analyses for FH-genes (LDLR and PCSK9), serum lipids, and ATT detected by X-ray at the Kanazawa University Hospital and National Cerebral and Cardiovascular Center Research Institute were included in this study. Receiver operating characteristic (ROC) analyses were conducted to determine a better cut-off value of ATT that predicts the pathogenic mutation of FH.

RESULTS

The ROC analyses revealed that the best cut-off values of ATT are 7.6 mm for male and 7.0 mm for female, with the sensitivities/specificities of 0.83/0.83 for male and 0.86/0.85 for female, respectively. If the thresholds of ATT of 8.0/7.5 mm and 7.5/7.0 mm were applied to the diagnosis of male/female FH, the sensitivities/specificities predicting the pathogenic mutation of FH by the 2017 JAS FH clinical criteria would be 0.82/0.90 and 0.85/0.88, respectively.

CONCLUSIONS

These results suggest that the cut-off value of ATT detected by X-ray is obviously lower than 9.0 mm, which was adopted by the 2017 JAS FH clinical criteria.

Risk of Non-Alcoholic Fatty Liver Disease in Xanthelasma Palpebrarum

Background

Xanthelasma palpebrarum (XP) is a sign of hyperlipidemia and is closely linked to atherosclerosis. Since fatty liver shares similar risk factors with atherosclerosis, we hypothesized that patients with XP are also at risk of non-alcoholic fatty liver disease (NAFLD).

Methods

In this retrospective cohort study, 37 patients with XP were compared with sex- and age-matched controls undergoing general health examination. Moreover, demographic information and lipid profiles were compared. The risk of NAFLD was evaluated using the hepatic steatosis and ZJU indices. In addition, we analyzed publicly available RNA sequencing data from the GSE48452 and GSE61260 datasets in the Gene Expression Omnibus database.

Findings

Patients with XP had higher scores of hepatic steatosis index (37 ± 1.13 vs 32 ± 0.82, p=0.0006) and ZJU index (38.77 ± 1.0 vs 33.88 ± 0.74, p=0.0002). In addition, they had higher levels of lipid parameters, including total cholesterol, low-density lipoprotein (LDL), and fasting glucose. Among patients with fatty liver, individuals presenting with XP showed higher serum levels of total cholesterol (216 ± 10.4 vs 188.9 ± 7.6, p=0.04), fasting glucose (117.1 ± 6.4 vs 98.3 ± 2.4, p=0.002), and low-density lipoprotein (145.1 ± 8.7 vs 115.6 ± 6.4, p=0.009) than those without XP. In gene expression analysis, individuals presenting with non-alcoholic steatohepatitis showed higher Z scores of xanthelasma than those without non-alcoholic steatohepatitis.

Conclusion

Our results suggest that individuals with XP have a higher risk of progression to NAFLD and develop a more severe dyslipidemia.

Polygenic risk scores for low-density lipoprotein cholesterol and familial hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal dominant monogenic disorder characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C) and an increased risk of premature coronary artery disease (CAD). Recently, it has been shown that a high polygenic risk score (PRS) could be an independent risk factor for CAD in FH patients of European ancestry. However, it is uncertain whether PRS is also useful for risk stratification of FH patients in East Asia. We recruited and genotyped clinically diagnosed FH (CDFH) patients from the Kanazawa University Mendelian Disease FH registry and controls from the Shikamachi Health Improvement Practice genome cohort in Japan. We calculated PRS from 3.6 million variants of each participant (imputed from the 1000 Genome phase 3 Asian dataset) for LDL-C (PRS_LDLC) using a genome-wide association study summary statistic from the BioBank Japan Project. We assessed the association of PRS_LDLC with LDL-C and CAD among and within monogenic FH, mutation negative CDFH, and controls. We tested a total of 1223 participants (376 FH patients, including 173 with monogenic FH and 203 with mutation negative CDFH, and 847 controls) for the analyses. PRS_LDLC was significantly higher in mutation negative CDFH patients than in controls (p = 3.1 × 10^-13). PRS_LDLC was also significantly linked to LDL-C in controls (p trend = 3.6 × 10^-4) but not in FH patients. Moreover, we could not detect any association between PRS_LDLC and CAD in any of the groups. In conclusion, mutation negative CDFH patients demonstrated significantly higher PRS_LDLC than controls. However, PRS_LDLC may have little additional effect on LDL-C and CAD among FH patients.

Diagnosis and Management of Sitosterolemia 2021

Sitosterolemia is an inherited metabolic disorder characterized by increased levels of plant sterols, such as sitosterol. This disease is caused by loss-of-function genetic mutations in ATP-binding cassette (ABC) subfamily G member 5 or member 8 ( ABCG5 or ABCG8 , respectively), both of which play important roles in selective excretion of plant sterols from the liver and intestine, leading to failure to prevent absorption of food plant sterols. This disorder has been considered to be extremely rare. However, accumulated clinical data as well as genetics suggest the possibility of a much higher prevalence. Its clinical manifestations resemble those observed in patients with familial hypercholesterolemia (FH), including tendon xanthomas, hyper LDL-cholesterolemia, and premature coronary atherosclerosis. We provide an overview of this recessive genetic disease, diagnostic as well as therapeutic tips, and the latest diagnostic criteria in Japan.

Homozygous Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an inherited disorder with retarded clearance of plasma LDL caused by mutations of the genes involved in the LDL receptor-mediated pathway and most of them exhibit autosomal dominant inheritance. Homozygotes of FH (HoFH) may have plasma LDL-C levels, which are at least twice as high as those of heterozygous FH (HeFH) and therefore four times higher than normal levels. Prevalence of HoFH had been estimated as 1 in 1,000,000 before but more recent genetic analysis surveys predict 1 in 170,000 to 300,000. Since LDL receptor activity is severely impaired, HoFH patients do not or very poorly respond to medications to enhance activity, such as statins, and have a poorer prognosis compared to HeFH. HoFH should therefore be clinically distinguished from HeFH. Thorough family studies and genetic analysis are recommended for their accurate diagnosis.

Fatal cardiovascular complications could develop even in the first decade of life for HoFH, so aggressive lipid-lowering therapy should be initiated as early as possible. Direct removal of plasma LDL by lipoprotein apheresis has been the principal measure for these patients. However, this treatment alone may not achieve stable LDL-C target levels and combination with drugs should be considered. The lipid-lowering effects of statins and PCSK9 inhibitors substantially vary depending on the remaining LDL receptor activity of individual patients. On the other hand, the action an MTP inhibitor is independent of LDL receptor activity, and it is effective in most HoFH cases.

This review summarizes the key clinical issues of HoFH as well as insurance coverage available under the Japanese public healthcare system.

Prevalence and Impact of Apolipoprotein E7 on LDL Cholesterol Among Patients With Familial Hypercholesterolemia

Background: It has been suggested that a rare mutant apolipoprotein E7, APOE7 (p.Glu262Lys, p.Glu263Lys), has been identified to be associated with hyperlipoproteinemia in the general population. Moreover, its prevalence has been shown to be 0.005-0.06%. However, there are no prior data regarding its prevalence and impact on serum lipids in patients with familial hypercholesterolemia (FH). Methods: We recruited 1,138 patients with clinically diagnosed FH [mean age = 48, men = 512, median low-density lipoprotein (LDL) cholesterol = 231 mg/dl]. The coding regions of three FH genes (LDLR, APOB, and PCSK9) and apolipoprotein E (APOE) gene were sequenced. We investigated the prevalence and impact of APOE7 mutant on serum lipid levels in patients with FH. Results: We identified 29 patients (2.5 %) with a mutant APOE7 (heterozygote), which is apparently much higher than that of the general population. Moreover, when we focus on those without FH mutation (n = 540), we identified 21 patients (3.9 %) with a mutant APOE7. Patients with a mutant APOE7 exhibited significantly higher median LDL cholesterol and triglyceride levels compared with those without this rare mutant (249 vs. 218 mg/dl, p < 0.05, 216 vs. 164 mg/dl, p < 0.05, respectively). Moreover, LDL cholesterol levels in the APOE7-oligogenic FH individuals, with a pathogenic mutation in FH genes and APOE7 mutant, were significantly higher than that in monogenic FH patients (265 vs. 245 mg/dl, p < 0.05). Conclusion: We identified more patients with a mutant APOE7 than expected among those diagnosed with FH clinically, especially among those without FH-causing mutation. This implies a mutant APOE7 may be one of the causes FH, especially among those without FH mutations.

Challenges of Precision Medicine for Atherosclerotic Cardiovascular Disease Based on Human Genome Information

Precision or personalized medicine is currently gaining a lot of attention. Clinical evidence for its effectiveness has been established based on randomized clinical trials accounting for classical risk factors, such as hypertension, diabetes, and serum lipids. However, besides such classical risk factors, the genetic background should be considered, at least for heritable traits, including atherosclerotic cardiovascular disease (ASCVD). Such classical risk factors are almost always incidents that have already occurred in which it may be too late to start treatment, instead of indicators of presymptomatic state. Human genome information is associated with most traits, including ASCVD. Two methods of implementing precision medicine for ASCVD using human genome information are currently being investigated: the use of rare genetic variations that have large effect sizes and polygenic risk scores that are composed of multiple common genetic variations. This review article emphasizes the importance of clinical as well as genetic diagnoses when implementing precision medicine. Precision medicine should be considered based on comprehensive genetic analyses, encompassing rare to common genetic variations.

Prognostic impact of cascade screening for familial hypercholesterolemia on cardiovascular events

BACKGROUND

Familial hypercholesterolemia (FH) is an autosomal dominant disorder mainly caused by mutations in the low-density lipoprotein (LDL) receptor or associated genes, resulting in elevated serum cholesterol levels and an increased risk of premature atherosclerotic cardiovascular disease (ASCVD).

OBJECTIVE

We aimed to evaluate the prognostic impact of cascade screening for FH.

METHODS

We retrospectively investigated the health records of 1050 patients with clinically diagnosed FH, including probands and their relatives who were cascade-screened, who were referred to our institute. We used Cox models that were adjusted for established ASCVD risk factors to assess the association between cascade screening and major adverse cardiac events (MACE). The median period of follow-up evaluating MACE was 12.3 years (interquartile ranges [IQR] = 9.1-17.5 years), and MACE included death associated with ASCVD, or acute coronary syndrome.

RESULTS

During the observation period, 113 participants experienced MACE. The mean age of patients identified through cascade screening was 18-years younger than that of the probands (38.7 yr vs. 57.0 yr, P < 0.0001), with a lower proportion of ASCVD risk factors. Interestingly, patients identified through cascade screening under milder lipid-lowering therapies were at reduced risk for MACE (hazard ratio [HR] = 0.67; 95%CI = 0.44 to 0.90; P = 0.0044) when compared with the probands, even after adjusting for those known risk factors, including age, and prior ASCVD.

CONCLUSIONS

The identification of patients with FH via cascade screening appeared to result in better prognosis.

Familial Hypercholesterolemia: A Narrative Review on Diagnosis and Management Strategies for Children and Adolescents

Familial hypercholesterolemia (FH) is a relatively common inherited disorder caused by deleterious mutation(s) in the low-density lipoprotein (LDL) receptor or its associated genes. Given its nature as a heritable disease, any useful screening scheme, including universal, and cascade screening, allows for the early identification of patients with FH. Another important aspect to note is that early diagnosis associated with appropriate treatment can promote better prognosis. However, most clinical diagnostic criteria for adults have adopted clinical elements, such as physical xanthomas and family history, both of which are usually obscure and/or difficult to obtain in children and adolescents. Moreover, LDL cholesterol levels fluctuating considerably during adolescence, hindering the timely diagnosis of FH. In addition, recent advancements in human genetics have revealed several types of FH, including conventional monogenic FH, polygenic FH caused by common single nucleotide variations (SNV) accumulation associated with elevated LDL cholesterol, and oligogenic FH with multiple deleterious genetic variations leading to substantially elevated LDL cholesterol. The aforementioned findings collectively suggest the need for amassing information related to genetics and imaging, in addition to classical clinical elements, for the accurate diagnosis of FH in this era of personalized medicine. The current narrative review summarizes the current status of the clinical and genetic diagnosis of FH in children and adolescents, as well as provide useful management strategies for FH in children and adolescents based on currently available clinical evidence.

The Digenic Causality in Familial Hypercholesterolemia: Revising the Genotype-Phenotype Correlations of the Disease

Genetically inherited defects in lipoprotein metabolism affect more than 10 million individuals around the globe with preponderance in some parts where consanguinity played a major role in establishing founder mutations. Mutations in four genes have been so far linked to the dominant and recessive form of the disease. Those players encode major proteins implicated in cholesterol regulation, namely, the low-density lipoprotein receptor (LDLR) and its associate protein 1 (LDLRAP1), the proprotein convertase substilin/kexin type 9 (PCSK9), and the apolipoprotein B (APOB). Single mutations or compound mutations in one of these genes are enough to account for a spectrum of mild to severe phenotypes. However, recently several reports have identified digenic mutations in familial cases that do not necessarily reflect a much severe phenotype. Yet, data in the literature supporting this notion are still lacking. Herein, we review all the reported cases of digenic mutations focusing on the biological impact of gene dosage and the potential protective effects of single-nucleotide polymorphisms linked to hypolipidemia. We also highlight the difficulty of establishing phenotype-genotype correlations in digenic familial hypercholesterolemia cases due to the complexity and heterogeneity of the phenotypes and the still faulty in silico pathogenicity scoring system. We finally emphasize the importance of having a whole exome/genome sequencing approach for all familial cases of familial hyperlipidemia to better understand the genetic and clinical course of the disease.

A reassessment of the Japanese clinical diagnostic criteria of familial hypercholesterolemia in a hospital-based cohort using comprehensive genetic analysis

Background

Clinical diagnostic criteria of familial hypercholesterolemia (FH) in Japan include LDL cholesterol ​≥ ​180 ​mg/dL, Achilles tendon thickness ​≥ ​9.0 ​mm, and family history. However, few data exist regarding its validation.

Design and Methods

A series of 680 participants, with a mean LDL cholesterol of 175 ​mg/dL were enrolled at Kanazawa University Hospital between 2006 and 2018. All had full assessments of, LDL cholesterol, Achilles tendon X-rays, family history records, and genetic analysis of FH-associated genes (LDLR, APOB, and PCSK9). The area under the curve (AUC) of receiver operating characteristic (ROC) curve analysis predicting the presence of FH mutations by each clinical marker were assessed.

Results

The optimal cutoff values predicting the presence of an FH-associated mutation were 181 ​mg/dL for LDL cholesterol and ≥7.0 ​mm for Achilles tendon thickness. AUCs predicting FH mutations were 0.827 for Achilles tendon thickness ≥9.0 ​mm, 0.889 for LDL cholesterol ≥180 ​mg/dL, and 0.906 for family history. If Achilles tendon thickness ≥7.0 ​mm was used as a clinical criterion, then 41 participants (6%) were newly diagnosed with FH and 86 (12%) were newly misclassified as FH.

Conclusions

Current clinical diagnostic criteria of FH were validated in this cohort. We recommend considering a tentative diagnosis of “potential FH” if the Achilles tendon thickness is ​≥ ​7.0 ​mm and <9.0 ​mm rather than dismissing a diagnosis of FH.

•

Clinical diagnostic criteria of FH in Japan were well validated.

•

The best cutoff value of ATT for predicting FH mutation was 7.0 ​mm.

•

Threshold of ATT ≥7.0 ​mm increased the sensitivity to diagnose FH.