PLASMA-LIPOPROTEIN COMPOSITIONAL DIFFERENCES IN PRIMARY HYPERCHOLESTEROLAEMIAS

Background and Aim: To identify lipoprotein compositional differences to be used as discriminants between Familial Hypercholesterolaemic (FH ) and Familial Combined Hyperlipidaemic type IIa (FCH-IIa) patients. M ethods and Results: At the Lipid Clinic (reference centre) of the Hosp ital Clinico Universitario at the University of Valencia (Spain) twent y FCH-IIa patients (12 females and 8 males, age 45 +/- 10 years) and F H 20 patients (10 females and 10 males, age 43 +/- 14 years) were comp ared with 20 healthy non-related subjects (10 females and 10 males). D iagnosis was based on the recommendations of the National Cholesterol Education Program guidelines. Lipid and apoprotein analyses were condu cted on lipoproteins that were isolated by ultracentrifugation from fa sting venous plasma. FH subjects had significantly higher plasma LDL-c holesterol and LDL-apo B values than FCH-IIa subjects: 7.90 +/- 1.57 m mol/l and 16.8 +/- 2.3 g/l vs 5.82 +/- 1.47 mmol/l and 14.3 +/- 2.1 g/ l respectively; p < 0.01. These values were significantly lower in con trols: 3.11 +/- 0.78 mmol/l and 7.9 +/- 1.4 g/l respectively; p < 0.01 . The cholesterol, triglyceride and apolipoprotein B content of VLDL w as significantly (p < 0.05) higher in FCH-IIa subjects (0.73 +/- 0.29, 0.84 +/- 0.37 and 1.45 +/- 0.91 g/l) than in FH (0.57 +/- 0.28 mmol/l , 0.47 +/- 0.23 mmol/l and 0.67 +/- 0.43 g/l) and controls (0.42 +/- 0 .19 mmol/l, 0.44 +/- 0.27 mmol/l and 0.53 +/- 0.22 g/l). The total cho lesterol/apo B ratio and the total cholesterol + triglycerides/apo B r atio were significantly lower in FCH-IIa than in FH and controls. Conc lusions: VLDL particles from the FCH-IIa subjects were lipid enriched compared to FH and control subjects. Conversely, the FH subjects had h igher LDL-cholesterol and LDL-Apo B levels than the FCH-IIa subjects. The VLDL particles in FCH-IIa and the LDL particles in FH were mainly abnormal compared to controls. These compositional differences can be useful to support clinical diagnosis of FH and FCH-IIa when other labo ratory techniques are not available. (C) 1997, Medikal Press.