Familial hypercholesterolaemia (FH) is caused by mutations in lipid metabolism genes, predominantly in low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin-type 9 (PCSK9) and LDL receptor adaptor protein 1 (LDLRAP1). The prevalence of genetically confirmed FH and the detection rate of pathogenic variants (PV) amongst clinically diagnosed patients is not well established. Targeted next-generation sequencing of LDLR, APOB, PCSK9 and LDLRAP1 was performed on 372 clinically diagnosed Malaysian FH subjects. Out of 361 variants identified, 40 of them were PV (18 = LDLR, 15 = APOB, 5 = PCSK9 and 2 = LDLRAP1). The majority of the PV were LDLR and APOB, where the frequency of both PV were almost similar. About 39% of clinically diagnosed FH have PV in PCSK9 alone and two novel variants of PCSK9 were identified in this study, which have not been described in Malaysia and globally. The prevalence of genetically confirmed potential FH in the community was 1:427, with a detection rate of PV at 0.2% (12/5130). About one-fourth of clinically diagnosed FH in the Malaysian community can be genetically confirmed. The detection rate of genetic confirmation is similar between potential and possible FH groups, suggesting a need for genetic confirmation in index cases from both groups. Clinical and genetic confirmation of FH index cases in the community may enhance the early detection of affected family members through family cascade screening.

Dyslipidaemia is a major cause of morbidity and mortality. The aims of this study are to determine the prevalence of dyslipidaemia subtypes, the proportions of lipid-lowering therapy (LLT) use, and the achievement of low-density lipoprotein cholesterol (LDL-C) treatment targets for high-risk (HR) and very high-risk (VHR) Malaysians. This cross-sectional study involves 5279 participants across 11 states in Malaysia. The data were obtained through a standardised questionnaire, anthropometric measurements, venous glucose and lipid profile. The participants with existing cardiovascular disease (CVD) or diabetes with at least one of the other major risk factors (smoking, hypertension or dyslipidaemia) were grouped into the VHR category. Other participants were risk-categorised using the Framingham General CVD Risk Score (FRS-CVD). The prevalence of elevated LDL-C, LLT use and LDL-C target were set according to respective risk categories. Pearson’s chi-squared test was used to test the difference in the proportions. The mean ± standard deviation (SD) age was 41.1 ± 14.8 years, and 62.2% (3283/5279) of the group were females. Within the participant group, 51.5% were found to have elevated total cholesterol, 28.8% had low HDL-C, and 33.8% had high triglyceride. As for elevated LDL-C, 9.8% were in VHR, 8.6% in HR, 5.8% in MR and 34.9% in LR categories. Among the VHR group, 75.8% were not on LLT, and only 15.9% achieved the LDL-C target. As for the HR category, 87.7% were not on LLT, and only 16.1% achieved the LDL-C target. Dyslipidaemia is highly prevalent among Malaysians. The majority of VHR and HR participants were not on LLT and did not achieve LDL-C treatment targets. Proactive programs are warranted to combat dyslipidaemia-associated CVD events in these groups.

Rationale: Homozygous familial hypercholesterolemia (HoFH) is a rare inherited disorder with an extremely elevated level of low-density lipoprotein (LDL) cholesterol (LDL-C) and accelerated premature coronary artery disease (PCAD). It is primarily caused by a single pathogenic variant of the LDL receptor ( LDLR ) gene. This report presents 2 rare and unrelated cases of HoFH with compound LDLR mutations. These 2 individuals presented with atypical clinical features and demonstrated variable degrees of hypercholesterolemia. Patient concerns: Case 1 is a 36-year-old Malay woman identified during family cascade screening with a pretreated LDL-C of 8.5 mmol/L and a strong family history of PCAD. Case 2 is a 58-year-old Indian woman discovered to have a pretreated LDL-C of 5.2 mmol/L during routine health screening, without a significant family history of hypercholesterolemia or PCAD. Neither patient demonstrated tendon xanthomas or other lipid stigmata. Diagnoses: Both patients underwent lipid profiling and targeted next-generation sequencing of FH-related genes ( LDLR , APOB , PCSK9 , ABCG5 , and ABCG8 ). Two novel LDLR variants were identified in exon 18: c.2548-1_2548delGAinsTC (pathogenic) and c.2556_2557insTCAGTCTGG (p.Leu853Serfs*12; likely pathogenic) and classified according to American College of Medical Genetics and Genomics guidelines. Case 1 was homozygous for both variants, while Case 2 was homozygous for the splice-site variant and heterozygous for the frameshift variant. Interventions: Both patients received guideline-directed lipid-lowering therapy and ongoing cardiovascular risk management. Outcomes: Despite biallelic LDLR variants, both patients demonstrated relatively milder hypercholesterolemia and absence of classical HoFH stigmata. Lessons: The LDLR variants located in exon 18 affecting the cytoplasmic tail domain may be associated with attenuated clinical expression. Recognition of genotype–phenotype variability is crucial for accurate diagnosis, risk stratification, and individualized management of HoFH.