Lipoprotein phenotyping shows triglyceride 340 mg/dL, total cholesterol 180 mg/dL, pre-beta-lipoprotein fraction increased, beta-lipoprotein normal, no chylomicrons, turbid serum. Which hyperlipoproteinemia is most suggested?

Lipoprotein phenotyping shows triglyceride 340 mg/dL, total cholesterol 180 mg/dL, pre-beta-lipoprotein fraction increased, beta-lipoprotein normal, no chylomicrons, turbid serum. Which hyperlipoproteinemia is most suggested?

• A. Type IV hyperlipoproteinemia
• B. Type I hyperlipoproteinemia
• C. Type II hyperlipoproteinemia
• D. Type III hyperlipoproteinemia

Answer: (A)

The key idea is that the pattern points to excess triglyceride-rich lipoproteins, specifically VLDL, rather than LDL or chylomicrons. Pre-beta lipoprotein corresponds to VLDL on electrophoresis, so an increased pre-beta fraction means more VLDL is circulating. Beta-lipoprotein represents LDL and is normal here, indicating LDL isn’t the main problem. No chylomicrons are present in fasting serum, so a chylomicron-rich disorder is unlikely. With a triglyceride level elevated (turid serum due to excess TG-rich lipoproteins), but cholesterol not markedly elevated and without chylomicrons or abnormal LDL, this fits endogenous hypertriglyceridemia driven by increased VLDL production or decreased clearance. That pattern is characteristic of Type IV hyperlipoproteinemia.

The key idea is that the pattern points to excess triglyceride-rich lipoproteins, specifically VLDL, rather than LDL or chylomicrons. Pre-beta lipoprotein corresponds to VLDL on electrophoresis, so an increased pre-beta fraction means more VLDL is circulating. Beta-lipoprotein represents LDL and is normal here, indicating LDL isn’t the main problem. No chylomicrons are present in fasting serum, so a chylomicron-rich disorder is unlikely.

With a triglyceride level elevated (turid serum due to excess TG-rich lipoproteins), but cholesterol not markedly elevated and without chylomicrons or abnormal LDL, this fits endogenous hypertriglyceridemia driven by increased VLDL production or decreased clearance. That pattern is characteristic of Type IV hyperlipoproteinemia.