An autosomal recessively inherited disorder characterized by the accumulation of intermediate-density lipoprotein (IDL or broad-beta-lipoprotein). IDL has a CHOLESTEROL to TRIGLYCERIDES ratio greater than that of VERY-LOW-DENSITY LIPOPROTEINS. This disorder is due to mutation of APOLIPOPROTEIN E, a receptor-binding component of VLDL and CHYLOMICRONS, resulting in their reduced clearance and high plasma levels of both cholesterol and triglycerides.