Background: Severe hypertriglyceridemia (SHTG) is associated with acute pancreatitis, metabolic dysfunction, and increased cardiovascular risk. Its genetic architecture ranges from rare biallelic variants causing familial chylomicronemia syndrome (FCS) to more prevalent polygenic or multifactorial chylomicronemia syndromes (MCS). Methods: We systematically reviewed scientific literature up to 2025 for studies reporting genetic data, clinical features, or therapeutic outcomes in adults with triglycerides (TG) ≥ 500 mg/dL. Extracted data were synthesized for genotype, polygenic risk score (PRS), TG levels, metabolic comorbidities, hepatic steatosis, pancreatitis, and treatment response. Results: Ten studies (n = 2521) were included. FCS due to biallelic LPL, APOC2, GPIHBP1, or LMF1 variants accounted for 2800 mg/dL) with pancreatitis prevalence (>70%). APOA5, APOC3, and APOB variants were associated with intermediate TG levels and high rates of metabolic dysfunction-associated steatotic liver disease (MASLD). Polygenic hypertriglyceridemia represented ~70–80% of cases, with TG ≈ 2200 mg/dL and pancreatitis prevalence 15–20%, largely modulated by metabolic triggers. MASLD was present in >70% of polygenic cases, supporting a “two-hit” model where hepatic overproduction of TG-rich lipoproteins amplifies TG excess. Interventional trials demonstrated TG reductions with APOC3 antisense therapy (70–80%) and ANGPTL3 inhibition (50–55%), while GLP-1RA significantly reduced hepatic fat (30–35%) and resolved NASH in up to 59% of patients. Conclusions: SHTG displays a genotype–phenotype gradient: FCS is linked to recurrent pancreatitis, whereas polygenic/MCS forms are closely associated with MASLD and metabolic dysfunction. These findings support a precision-medicine approach integrating genetic testing and PRS-guided strategies—prioritizing APOC3/ANGPTL3 inhibitors for FCS and combined TG-lowering plus metabolic therapies for MCS—to reduce pancreatitis recurrence and liver disease.

Background: The antisense oligonucleotide against APOC3 mRNA volanesorsen was recently introduced to treat Familial Chylomicronemia Syndrome (FCS). Cases of decreased platelet count are reported among patients treated with volanesorsen. The aim of the study was to evaluate platelet function and thrombin generation (TG) assessment in FCS patients receiving volanesorsen. We performed a cross-sectional study on FCS patients treated with volanesorsen. Methods: Changes in platelet count PLC were assessed from baseline to Tw12 and Tw36. To assess TG, samples were processed by CAT (with PPP-reagent LOW). The results were expressed by the thrombogram graphic (thrombin variation over time); LagTime; endogenous thrombin potential (ETP); peak; time to reach peak (ttpeak), StartTail and Velocity Index. Platelet aggregation was assessed by testing different agonists using the turbidimetry method. Results: Four FCS patients and four matched healthy controls were included in the present study. Changes in PLC were 30% at Tw12 and 34% at Tw36. Thrombin generation results showed values in the normal range (for patients and controls, respectively, LagTime:10.42 ± 4.40 and 9.25 ± 0.99; ttPeak:14.33 ± 4.01 and 13.10 ± 0.67; StartTail: 32.13 ± 3.54 and 29.46 ± 1.69; Velocity Index: 20.21 ± 3.63 and 33.05 ± 13.21; ETP: 599.80 ± 73.47 and 900.2 ± 210.99; peak value: 76.84 ± 1.07 and 123.30 ± 39.45) and no significant difference between cases and controls. Platelet aggregation test showed values in range, with no significant difference compared to healthy controls. Conclusions: Our study showed for the first time that no significant changes in general hemostasis assessed by TG and in platelet function were observed in FCS patients receiving volanesorsen.

Background: The antisense oligonucleotide against APOC3 mRNA volanesorsen was recently introduced to treat Familial Chylomicronemia Syndrome (FCS). Cases of decreased platelet count are reported among patients treated with volanesorsen. The aim of the study is to evaluate platelet function and thrombin generation (TG) assessment in FCS patients receiving volanesorsen. We performed a cross-sectional study on FCS patients treated with volanesorsen. Methods: changes in PLC were assessed from baseline to Tw12 and Tw36. To assess TG, samples were processed by CAT (with PPP-reagent LOW). The results were expressed by the trombogram graphic (thrombin variation over time); lagTime; Endogenous Thormbin Potential(ETP); peak; time to reach peak(ttpeak), startTail e velocity Index. Platelet aggregation was assessed by testing different agonists using turbidimetry method. Results: Four FCS patients and 4 matched healthy controls were included in the present study. Changes in PLC at Tw12 was 30% and 34% at T36w. Thrombin generation results show values in normal range (for patients and controls respectively lagTime:10,42±4,40 and 9,25±0,99; ttPeak:14,33± 4,01 and 13,10±0,67; startTail:32,13±3,54 and 29,46±1,69; velocityIndex:20,21±3,63 and 33,05±13,21; ETP 599,80±73,47 and 900,2±210,99; peak value 76,84±1,07 and 123,30±39,45) and no significant difference between cases and controls. Platelet aggregation test showed values in range with no significant difference with healthy controls Conclusions: Our study showed for the first time that no significant changes in the general haemostasis assessed by TG and in platelet function have been observed in FCS patients receiving volanesorsen.