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 apolipoproteins e, a receptor-binding component of VLDL and chylomicrons, resulting in their reduced clearance and high plasma levels of both cholesterol and triglycerides.