Cascade Screening and Treatment Initiation in Young Adults with Heterozygous Familial Hypercholesterolemia

"I don't think people should die young": perspectives of parents with children diagnosed with familial hypercholesterolemia

Familial Hypercholesterolemia (FH) is an inherited disorder that significantly increases an individual's risk of developing premature cardiovascular disease (CVD). Early intervention involving lifestyle modification and medication is crucial in preventing CVD. Prior studies have shown that lipid-lowering therapy in children is safe and effective. Despite FH being a treatable and manageable condition, the condition is still underdiagnosed and undertreated. Universal lipid screening (ULS) in children has been recommended by some medical experts in the United States as a strategy to identify cases of FH and maximize the benefits of early invention. However, lipid screening is not routinely offered in pediatric clinics. This study aimed to explore parental experience with FH diagnosis in their children, identify key facilitators and barriers in children's diagnosis and care, and examine parental perspectives on ULS in children in the United States. A total of fourteen semi-structured interviews were conducted with participants recruited through the Family Heart Foundation. Thematic analysis identified three key themes: role of family history in facilitating child's FH diagnosis, barriers and challenges in post-diagnosis care, and attitudes towards ULS in children. All participants supported ULS in children and emphasized the value of early diagnosis and treatment for FH. However, a lack of guidance or referral after the child's diagnosis was a concern raised by many participants. This underscores the need for accessible and comprehensive care amid ongoing efforts to increase pediatric diagnosis of FH.

Algorithm for detection and screening of familial hypercholesterolemia in Lithuanian population

BACKGROUND

Familial hypercholesterolemia (FH) is one of the most common autosomal dominant diseases. FH causes a lifelong increase in low-density lipoprotein cholesterol (LDL-C) levels, which in turn leads to atherosclerotic cardiovascular disease. The incidence of FH is widely underestimated and undertreated, despite the availability and effectiveness of lipid-lowering therapy. Patients with FH have an increased cardiovascular risk; therefore, early diagnosis and treatment are vital. To address the burden of FH, several countries have implemented national FH screening programmes. The currently used method for FH detection in Lithuania is mainly based on opportunistic testing with subsequent cascade screening of index cases' first-degree relatives.

METHODS

A total of 428 patients were included in this study. Patients with suspected FH are referred to a lipidology center for thorough evaluation. Patients who met the criteria for probable or definite FH according to the Dutch Lipid Clinic Network (DLCN) scoring system and/or had LDL-C > = 6.5 mmol/l were subjected to genetic testing. Laboratory and instrumental tests, vascular marker data of early atherosclerosis, and consultations by other specialists, such as radiologists and ophthalmologists, were also recorded.

RESULTS

A total of 127/428 (30%) patients were genetically tested. FH-related mutations were found in 38.6% (n = 49/127) of the patients. Coronary artery disease (CAD) was diagnosed in 13% (n = 57/428) of the included patients, whereas premature CAD was found in 47/428 (11%) patients. CAD was diagnosed in 19% (n = 9/49) of patients with FH-related mutations, and this diagnosis was premature for all of them.

CONCLUSIONS

Most patients in this study were classified as probable or possible FH without difference of age and sex. The median age of FH diagnosis was 47 years with significantly older females than males, which refers to the strong interface of this study with the LitHir programme. CAD and premature CAD were more common among patients with probable and definite FH, as well as those with an FH-causing mutation. The algorithm described in this study is the first attempt in Lithuania to implement a specific tool which allows to maximise FH detection rates, establish an accurate diagnosis of FH, excluding secondary causes of dyslipidaemia, and to select patients for cascade screening initiation more precisely.

Cascade screening for familial hypercholesterolemia should be organized at a national level

PURPOSE OF REVIEW

Patients with familial hypercholesterolemia (FH) have a markedly increased risk of premature cardiovascular disease. However, there are effective lipid-lowering therapies available to reduce the risk of cardiovascular disease. This makes it important to diagnose these patients. The most cost-effective strategy to diagnose patients with FH is to perform cascade screening. However, cascade screening as part of ordinary healthcare has not been very successful. Thus, there is a need to implement more efficient cascade screening strategies.

RECENT FINDINGS

Cascade screening for FH should be organized at a national level and should be run by dedicated health personnel such as genetic counsellors. As part of a national organization a national registry of patients with FH needs to be established. Moreover, for cascade screening to be effective, diagnosis of FH must be based on identifying the underlying mutation. There should preferably only be one genetics centre in each country for diagnosing FH, and this genetics centre should be an integrated part of the national cascade screening program.

SUMMARY

Cascade screening for FH is very effective and should be organized at a national level. Even a modest national cascade screening program can result in a large number of patients being identified.

Two Novel Disease-Causing Mutations in the LDLR of Familial Hypercholesterolemia

As an autosomal dominant disorder, familial hypercholesterolemia (FH) is mainly caused by pathogenic mutations in lipid metabolism-related genes. The aim of this study is to investigate the genetic mutations in FH patients and verify their pathogenicity. First of all, a pedigree investigation was conducted in one family diagnosed with FH using the Dutch Lipid Clinic Network criteria. The high-throughput sequencing was performed on three family members to explore genetic mutations. The effects of low-density lipoprotein receptor (LDLR) variants on their expression levels and activity were further validated by silico analysis and functional studies. The results revealed that LDLC levels of the proband and his daughter were abnormally elevated. The whole-exome sequencing and Sanger sequencing were used to confirm that there were two LDLR missense mutations (LDLR c.226 G > C, c.1003 G > T) in this family. Bioinformatic analysis (Mutationtaster) indicated that these two mutations might be disease-causing variants. In vitro experiments suggested that LDLR c.226 G > C and c.1003 G > T could attenuate the uptake of Dil-LDL by LDLR. In conclusion, the LDLR c.226 G > C and c.1003 G > T variants might be pathogenic for FH by causing uptake dysfunction of the LDLR.

Analysis of Rare Variants in Genes Related to Lipid Metabolism in Patients with Familial Hypercholesterolemia in Western Siberia (Russia)

The aim of this work was to identify genetic variants potentially involved in familial hypercholesterolemia in 43 genes associated with lipid metabolism disorders. Targeted high-throughput sequencing of lipid metabolism genes was performed (80 subjects with a familial-hypercholesterolemia phenotype). For patients without functionally significant substitutions in the above genes, multiplex ligation-dependent probe amplification was conducted to determine bigger mutations (deletions and/or duplications) in the LDLR promoter and exons. A clinically significant variant in some gene associated with familial hypercholesterolemia was identified in 47.5% of the subjects. Clinically significant variants in the LDLR gene were identified in 19 probands (73.1% of all variants identified in probands); in three probands (11.5%), pathogenic variants were found in the APOB gene; and in four probands (15.4%), rare, clinically significant variants were identified in genes LPL, SREBF1, APOC3, and ABCG5. In 12 (85.7%) of 14 children of the probands, clinically significant variants were detectable in genes associated with familial hypercholesterolemia. The use of clinical criteria, targeted sequencing, and multiplex ligation-dependent probe amplification makes it possible to identify carriers of rare clinically significant variants in a wide range of lipid metabolism genes and to investigate their influence on phenotypic manifestations of familial hypercholesterolemia.