Homozygous familial hypercholesterolemia (HoFH) in Germany: an epidemiological survey

Successful pharmacological management of a child with compound heterozygous familial hypercholesterolemia and review of the recent literature

Severe familial hypercholesterolemia (SFH) is characterized by markedly elevated low-density lipoprotein cholesterol (LDL-C) and severe early-onset cardiovascular disease if left untreated. We report on the decade-long therapeutic journey of a 15-year-old boy with SFH due to a severe compound heterozygous genotype. He presented at the age of 5 years with widespread xanthomas and LDL-C of 17.4 mmol/L. He was diagnosed with SFH, initially treated with colestyramine that was subsequently combined with simvastatin. At the age of 12 years, he was diagnosed to have supravalvular aortic stenosis and ezetimibe/atorvastatin was introduced in place of colestyramine/simvastatin. At the age of 14 years, he received triple therapy with evolocumab, initially at the recommended dose of 420 mg monthly and then reduced to 140 mg biweekly. Currently at the age of 15 years, he is on atorvastatin 40 mg ON, ezetimibe 10 mg OM, and evolocumab 140 mg biweekly, achieving LDL-C levels of 2.4 mmol/L. Genetic testing identified compound heterozygous mutations in the LDL receptor genes [c.(940 + 1_941-1) (1845 + 1_1846-1)dup] and exon 12, nucleotide c.1747 C > T, amino acid p.(His583Tyr). Medical management without lipoprotein apheresis can achieve target LDL-C in children with SFH. Our patient, who developed supravalvular aortic stenosis at the age of 12 years, needed early aggressive treatment when SFH guidelines and newer drugs for young children were unavailable. Our patient demonstrated that 140 mg biweekly of evolocumab has the same cholesterol-lowering effect as the recommended 420 mg monthly dose.

Overview of the current status of familial hypercholesterolaemia care in over 60 countries - The EAS Familial Hypercholesterolaemia Studies Collaboration (FHSC)

BACKGROUND AND AIMS

Management of familial hypercholesterolaemia (FH) may vary across different settings due to factors related to population characteristics, practice, resources and/or policies. We conducted a survey among the worldwide network of EAS FHSC Lead Investigators to provide an overview of FH status in different countries.

METHODS

Lead Investigators from countries formally involved in the EAS FHSC by mid-May 2018 were invited to provide a brief report on FH status in their countries, including available information, programmes, initiatives, and management.

RESULTS

63 countries provided reports. Data on FH prevalence are lacking in most countries. Where available, data tend to align with recent estimates, suggesting a higher frequency than that traditionally considered. Low rates of FH detection are reported across all regions. National registries and education programmes to improve FH awareness/knowledge are a recognised priority, but funding is often lacking. In most countries, diagnosis primarily relies on the Dutch Lipid Clinics Network criteria. Although available in many countries, genetic testing is not widely implemented (frequent cost issues). There are only a few national official government programmes for FH. Under-treatment is an issue. FH therapy is not universally reimbursed. PCSK9-inhibitors are available in ∼2/3 countries. Lipoprotein-apheresis is offered in ∼60% countries, although access is limited.

CONCLUSIONS

FH is a recognised public health concern. Management varies widely across countries, with overall suboptimal identification and under-treatment. Efforts and initiatives to improve FH knowledge and management are underway, including development of national registries, but support, particularly from health authorities, and better funding are greatly needed.

Treatment Preferences in Germany Differ Among Apheresis Patients with Severe Hypercholesterolemia

BACKGROUND

Severe hypercholesterolemia is a major risk factor of death in patients with coronary heart disease. New adjunctive drug therapies (proprotein convertase subtilisin/kexin type 9 [PCSK9] inhibitors) have gained approval in Europe and the USA.

OBJECTIVE

In this empirical study, we documented preferences regarding adjuvant drug therapy in apheresis-treated patients with severe familial hypercholesterolemia.

METHODS

We conducted a systematic literature search to identify patient-relevant outcomes in patients with severe hypercholesterolemia currently undergoing apheresis. Data were used to generate a semi-structured qualitative interview that enabled seven patient-relevant characteristics with three levels each to be identified. For the discrete choice experiment, an experimental design (7 × 3) was generated using NGene Software that consisted of 96 choices divided into eight blocks. The survey was conducted between November 2015 and April 2016 using computer-assisted personal interviews.

RESULTS

The survey was completed by 348 patients (64.9% male). The random parameter logit estimation showed predominance for the attribute 'reduction of LDL-C (low-density lipoprotein cholesterol) level'. 'Risk of myopathy' and 'frequency of apheresis' dominated next. Within the random parameter logit estimation, all coefficients were significant (P ≤ 0.01). The latent class analysis identified three patient groups. The first group (126 patients) found 'reduction of LDL-C level in blood' to be most important. This group focused solely on this treatment outcome independently of apheresis frequency or additional injections. The second group (106 patients) focused on three attributes: 'frequency of apheresis', 'risk of myopathy', and 'reduction of LDL-C level in blood'. Respondents clearly considered a high frequency of apheresis to have a negative impact. The third group (116 patients) demonstrated the highest preference for apheresis. These patients have adjusted to apheresis for > 10 years.

CONCLUSION

Regarding patient preference, clinical efficacy seems to dominate. Hence, 'reduction of LDC-C in blood' was ranked highest above patient-relevant modes of administration and adverse effects. In the patient groups identified, reduction of apheresis was important for only a subsegment (30%) of patients. Another 30% wanted effective LDL-C reduction by whatever means necessary. Most strikingly, another 30% preferred higher frequencies of apheresis.

Homozygous Familial Hypercholesterolemia in Spain

Background—

Homozygous familial hypercholesterolemia (HoFH) is a rare disease characterized by elevated plasma levels of low-density lipoprotein cholesterol (LDL-C) and extremely high risk of premature atherosclerotic cardiovascular disease. HoFH is caused by mutations in several genes, including LDL receptor ( LDLR ), apolipoprotein B ( APOB ), proprotein convertase subtilisin/kexin type 9 ( PCSK9 ), and LDL protein receptor adaptor 1 ( LDLRAP1 ). No epidemiological studies have assessed HoFH prevalence or the clinical and molecular characteristics of this condition. Here, we aimed to characterize HoFH in Spain.

Methods and Results—

Data were collected from the Spanish Dyslipidemia Registry of the Spanish Atherosclerosis Society and from all molecular diagnoses performed for familial hypercholesterolemia in Spain between 1996 and 2015 (n=16 751). Clinical data included baseline lipid levels and atherosclerotic cardiovascular disease events. A total of 97 subjects were identified as having HoFH—of whom, 47 were true homozygous (1 for APOB , 5 for LDLRAP1 , and 41 for LDLR ), 45 compound heterozygous for LDLR , 3 double heterozygous for LDLR and PSCK9 , and 2 double heterozygous for LDLR and APOB . No PSCK9 homozygous cases were identified. Two variants in LDLR were identified in 4.8% of the molecular studies. Over 50% of patients did not meet the classical HoFH diagnosis criteria. The estimated HoFH prevalence was 1:450 000. Compared with compound heterozygous cases, true homozygous cases showed more aggressive phenotypes with higher LDL-C and more atherosclerotic cardiovascular disease events.

Conclusions—

HoFH frequency in Spain was higher than expected. Clinical criteria would underestimate the actual prevalence of individuals with genetic HoFH, highlighting the importance of genetic analysis to improve familial hypercholesterolemia diagnosis accuracy.

Disease control via intensified lipoprotein apheresis in three siblings with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH), the prevalent monogenic form of hypercholesterolemia, carries the risk of premature coronary heart disease. Lipoprotein-apheresis is established in children with severe dyslipidemia. We present 3 siblings with a negative/negative residual low-density lipoprotein (LDL) receptor mutation (p.Trp577Arg), unresponsive to drug treatment.

OBJECTIVE

Intensified lipoprotein-apheresis is well tolerated and results in permanently low lipid values without harming the health-related quality of life in children.

METHODS

Three homozygous FH siblings, aged 7-13 years, had been treated with statins and ezetimibe for 12 months but still showed highly elevated low-density lipoprotein cholesterol (LDL-C) plasma concentrations. They were started on double-filtration plasmapheresis that was subsequently intensified according to plasma lipid levels.

RESULTS

Each lipoprotein apheresis session reduced LDL-C concentration by 66% to 70%. Treated plasma volume was doubled after 6 months due to a sustained rebound of LDL-C between sessions. However, the rebound remained unchanged. Only an increase in frequency of sessions to every 3 to 4 days resulted in acceptable pre-treatment LDL-C concentrations (Cmax). Neither cessation of statins nor reduction of plasma exchange volume to 1.5 fold in follow-up influenced Cmax. Intensified therapy did not harm health-related quality of life as assessed by PedsQL and was well tolerated.

CONCLUSIONS

In pediatric FH patients unresponsive to drug treatment, intensified lipoprotein apheresis can normalize plasma lipid levels. Apparently, treatment frequency rather than volume has greater influence on its efficacy. The potential burden of intensified therapy to daily life has to be regarded. Serum lipid levels in FH should be normalized to minimize cardiovascular risk.

Familial hypercholesterolemia: developments in diagnosis and treatment

BACKGROUND

Familial hypercholesterolemia (FH) is a congenital disorder of lipid metabolism characterized by a marked elevation of the plasma concentration of LDL (low-density lipoprotein) cholesterol beginning in childhood and by the early onset of coronary heart disease. It is among the commonest genetic disorders, with an estimated prevalence in Germany of at least 1 per 500 persons.

METHOD

Review of pertinent literature retrieved by a selective search.

RESULTS

FH is underdiagnosed and undertreated in Germany. It is clinically diagnosed on the basis of an elevated LDL cholesterol concentration (>190 mg/dL [4.9 mmol/L]), a family history of hypercholesterolemia, and early coronary heart disease, or the demonstration of xanthomas. The gold standard of diagnosis is the identification of the underlying genetic defect, which is possible in 80% of cases and enables the identification of affected relatives of the index patient. The recommended goals of treatment, based on the results of observational studies, are to lower the LDL cholesterol concentration by at least 50% or to less than 100 mg/dL (2.6 mmol/L) (for children: <135 mg/dL [3.5 mmol/L]). The target value is lower for patients with clinically overt atherosclerosis (<70 mg/dL [1.8 mmol/L]). Statins, combined with a health-promoting lifestyle, are the treatment of choice. Lipoprotein apheresis is used in very severe cases; its therapeutic effects on clinical endpoints and its side effect profile have not yet been documented in randomized controlled trials.

CONCLUSION

Familial hypercholesterolemia is a common disease that can be diagnosed simply and reliably on clinical grounds and by molecular genetic testing. Timely diagnosis and appropriate treatment can lower the risk of atherosclerosis in heterozygous patients to that of the general population.