Chylomicronemia Due to the Rare Hyperlipoproteinemia Type 3 Complicated by a Circulating Monoclonal Protein

The polygenic variety of chylomicronemia occurs in adults in whom factors such as obesity, diabetes, alcoholism, renal disease, and certain drugs can precipitate chylomicronemia. A rare cause of polygenic chylomicronemia is hyperlipoproteinemia type 3 (HLP3). We report on a 54-year-old male who presented with chylomicronemia with triglycerides (TG) >2000 mg/dL. From admission, the ratio of total cholesterol to total triglycerides was not below 0.2 but was closer to 0.5, suggesting that his condition was not classic chylomicronemia. We confirmed that the patient had HLP3 based on his very-low-density lipoprotein cholesterol (VLDL-C)/TG ratio, which was ≥0.3, and lipoprotein electrophoresis showing a broad beta band. Because he was not responsive to initial therapy, we considered an interferent impairing lipolysis and TG reduction. The interferent was an M-protein that may also have falsely elevated both apolipoprotein-B and direct-LDL-C levels. In this case study, we report on a patient with chylomicronemia resulting from HLP3 complicated by a circulating M-protein.