Chylomicronemia syndrome: Familial or not?

Background: Chylomicronemia syndrome (CS) is a metabolic condition characterized by severely elevated plasma triglycerides (>880 mg/dL) and high rates of morbidity and mortality. The syndrome can be classified into two major groups: monogenic familial chylomicronemia syndrome (FCS) and multifactorial chylomicronemia syndrome (MCS), the frequencies of which are ill-defined. Objective: The objective of the study was to characterize the prevalence of the most common and rarest subsets of this syndrome, MCS and FCS, respectively, in a single-center, real-world setting. Methods: This was a retrospective cross-sectional study of patients with plasma triglycerides ≥880 mg/dL. The criteria used for identification of patients with FCS were modeled after a Food and Drug Administration endorsed set of parameters. Less stringent criteria that removed the requirement for pancreatitis were used to classify MCS. Full criteria are described in detail in the article. Results: Of the 2,342,136 patient records queried, 578 had triglycerides ≥880 mg/dL (0.025%), of which 86 had a documented history of pancreatitis. Five patients who met the criteria for FCS were identified (three genetically confirmed), resulting in an estimated prevalence of ~1-2 per 1,000,000. On the other hand, MCS was identified in 186 patients, corresponding to an estimated prevalence of ~1 in 12,000. There were 5181 cases of pancreatitis (0.22% of the entire cohort), 86 of which occurred in subjects with triglycerides≥880 mg/dL (1.7% of cases of pancreatitis). Rates of pancreatitis in this subset were elevated at 6.5%, 100%, and 17.8%, among patients with MCS, FCS, and secondary hypertriglyceridemia, respectively. Conclusions: CS is an uncommon condition, but it is associated with significant complications, regardless of etiology. Among patients with CS, MCS was 40- to 60-fold more prevalent than FCS and associated with frequent morbidity. Therefore, disease recognition and treatment should extend to all forms of CS pursuant to the clinical presentation.