--Disease Characteristics-- Homozygous familial hypercholesterolemia, i.e.: Low-density lipoprotein (LDL) cholesterol greater than 500 mg/dL Autosomal dominant inheritance Early-onset tendon and tuberous xanthomas LDL receptor negative, i.e.: Receptor binding in cultured fibroblasts no more than 20% of normal OR Genotype with 2 previously described, disease-causing alleles Advanced coronary heart disease with relatively poor prognosis, i.e: Angina pectoris History of myocardial infarction Positive exercise tolerance test Atherosclerotic disease in proximal aorta or coronary arteries by ultrasound or angiogram None of the following: Unstable angina pectoris Left ventricular ejection fraction less than 30% Decompensated congestive heart failure Untreated ventricular tachycardia Moderate to severe aortic stenosis Other dyslipidemia Obstructive hepatobiliary disease