Correlation between chylomicronemia diagnosis scores and post-heparin lipoprotein lipase activity

•There was a significant difference in lipoprotein lipase activity between familial chylomicronemia and chylomicronemia.•The two published familial chylomicronemia scoring systems correlated with post-heparin lipoprotein lipase activity.•Both chylomicronemia scoring systems contribute to distinguish familial chylomicronemia from the multifactorial form. Sustained chylomicronemia is a defect in post-prandial triglyceride management characterized by severe hypertriglyceridemia (triglyceride > 10 mmol/L) due to functional or genetic defects in lipoprotein lipase (LPL)-mediated triglyceride-rich lipoprotein lipolysis. Familial chylomicronemia syndrome (FCS) is a rare mendelian form of chylomicronemia caused by loss-of–function variants in LPL or LPL-related genes. Most individuals with chylomicronemia however present multifactorial chylomicronemia (MCS), in which LPL bio-availability and activity are variable. FCS and MCS differ in terms of clinical characteristics and risk of disease, and diagnosis scoring systems have been proposed to accurately distinguish FCS from MCS. The aim of this study was to assess the strength of the relationship between plasma post-heparin LPL activity and two published chylomicronemia diagnosis scoring systems. Post-heparin plasma LPL activity was measured using colorimetric assays in a sample of 29 subjects with sustained chylomicronemia (20 FCS and 9 MCS). Chylomicronemia diagnosis scores were obtained for all subjects using the scoring system A (model A), which integrates apolipoprotein B and free glycerol, a surrogate marker of triglyceride hydrolysis, and the scoring system B (model B). Correlation analyses were conducted to estimate the linear relationship between LPL activity and the two diagnosis scoring systems. There was a significant (p