Biochemical investigations showed hypoalphalipoproteinaemia (with a faint fast-moving HDL band on polyacrylamide gel gradient electrophoresis and small arcs of HDL2 and HDL3 of low mobility determined by agarose gel immunoelectrophoresis), low total cholesterol (3.5-4.9 mmol l-1), slightly decreased cholesteryl ester/total cholesterol ratio (0.52-0.63), extremely low HDL cholesterol (0.20-0.21 mmol l-1), mild hypertriglyceridaemia (1.94-3.80 mmol l-1), and striking deficiency in apo A-I and apo A-II (0.45-0.72, 0.08-0.16 g l-1, respectively).