**9. Familial hypercholesterolemia**

Familial hypercholesterolemia is a metabolic disorder that occurs as a result of the absence or lack of LDL receptors in the liver. Since LDL molecules are removed from the circulation, very high LDL levels and premature atherosclerosis are observed. Familial hypercholesterolemia is thought to be approximately 1/500 of the homozygous form and approximately 1/1 million of the heterozygous form. Tendon xanthomas are pathognomonic signs for familial hypercholesterolemia. There is also an increase in the frequency of corneal arcus, xanthelasma.
