Type II hypercholesterolemia is due to

2. Type II: Familial Hypercholesterolaemia (FHC): A common disorder which has been extensively investigated.The disease is characterised by:Hyper b-lipoproteinemia (LDL |)Associated with increased total cholesterol |VLDL may be raised, hence total TG may be high. But plasma usually remains clear.Inheritance: Autosomal dominant; Frequency--0.2 percentEnzyme deficiency (metabolic defect): There is no enzyme deficiency. Metabolic defects are:An increased synthesis of apo-B |Defective catabolism of LDL. Deficiency of LDL receptors in fibroblasts demonstrated.Clinical features: (a) Xanthomas of tendinous and tuberous type have been described, (b) Corneal arcus, (c) Occasionally xanthelasma. Clinically most impoant is the increased incidence of atherosclerosis and premature cardiovascular diseases.Note: Type-II Pattern can develop as a result of hypothyroidism (secondary hyper or lipoproteinemia).Ref: M.N. Chatterjea - Textbook of Biochemistry, 8th edition, page no: 451