Although the usual diet may contain 150-250 mg of plant sterols, chiefly β-sitosterol, only trace amounts of these sterols have heretofore been found in human or animal blood and tissues. We now report elevated plant sterol levels in the blood and tissues of two sisters with extensive tendon xanthomas but normal plasma cholesterol levels. Besides β-sitosterolemia and xanthomatosis, no other physical, mental, or biochemical abnormalities were detected.
