CR II - Dyslipoproteinemias Flashcards
What dyslipoproteinemia is characterized by a deficiency in triglyceride transfer protein? What does this cause?
Abetalipoproteinemia - unable to assemble/secrete apoB containing lipoproteins from intestine or liver
Chylomicrons, VLDL, and LDL absent
As a result of abetalipoproteinemia, where are two places lipids accumulate? What are two other significant consequences?
Liver and intestine
Severe fat malabsorption and deficiencies in fat soluble vitamins
Untreated abetalipoproteinemia results in what three conditions in patients? What can treat the clinical signs?
Ataxia, retinitis pigmentosa, myopathy
Vitamin E treats clinical signs
What is deficient in Tangier disease? How does this involve cholesterol?
Deficiency in ABCA1
Cholesterol cannot be transferred from plasma membrane to HDL because it cannot leave inner leaflet of plasma membrane
What are three consequences of Tangier disease? What are 3 symptoms?
No HDL formation
Decreased LDL (due to no transfer of cholesterol to VLDL from HDL)
Cholesterol ester deposits in reticuloendothelial cells, bone marrow, and Schwann cells
Symptoms: peripheral neuropathy, hepatosplenomegaly, lymphadenopathy
What is deficient in familial hypercholesterolemia? How to Heterozygotes differ from Homozygotes? What are two major consequences?
Deficient in LDL receptor
Heterozygotes - 50% reduction in LDL receptors, plasma total cholesterol = 350
Homozygotes - rare, no function LDL receptors, plasma = 600-1200
Consequences - CHD and xanthomas (tend to be over joints)
What are three consequences of familial LCAT deficiency? What are 4 symptoms?
Consequences - block in reverse cholesterol transport, limited ability of HDL to acquire cholesterol, elevated blood cholesterol and triglycerides
Symptoms - free cholesterol collects in tissue, kidney disease, corneal clouding, mild tendency for atherosclerosis
What deficiency is common in Japan, a benign condition, characterized by cholesterol esters not able to transfer from HDL to other lipoproteins? What is true of Homozygotes? What is still possible? How?
CETP deficiency
Homozygotes have 4x elevated HDL and normal LDL
Reverse cholesterol transport still possible through cholesterol ester transport by SR-B1 receptors of liver and through endocarditis of HDL with multiple copies of apoE
What are the 5 classifications of hyperlipoproteinemias under the Frederickson classification?
Type I: hyperchylomicronemia - rare Type II: Hypercholesterolemia - common Type III: dysbetalipoproteinemia - rare Type IV: Hypertriglyceridemia - common Type V: Hyperlipogroteinemias - rare
Which type seems greatly increase triglycerides (up to 1000mg/dL) with only slightly or normal cholesterol? What are two causes? What are symptoms and treatment?
Type I: hyperchylomicronemia
Deficiency of LPL or apoC-II
Eruptive xanthomas, abdominal pain after eating high fat meal, recurrent pancreatitis
Treatment: low fat diet
Which type is common, characterized by elevated LDL? What is a primary cause and two secondary causes? What is it a major risk factor for?
Type II: Hypercholesterolemia
Causes: Familial hypercholesterolemia (primary) or obesity/diabetes (secondary)
Major risk factor for atherosclerosis
Which type is classified by increase triglycerides and cholesterol? What is a genetic cause? What are 2 symptoms? What is treatment?
Type III: dysbetalipoproteinemia
Homozygotes for apoE2 - ApoE with less affinity for receptor
Xanthomas and increased CHD risk
Treatment: dietary
What type is characterized by increased triglycerides with some hypercholesterolemia? What are 5 lifestyle causes?
Type IV: hypertriglyceridemia
Obesity, Type II Diabetes, Alcoholism, Progesterone-rich contraceptives, excess dietary carbohydrates
What type is rare, associated with both increased triglyceride and cholesterol levels due to increased chylomicrons and VLDL, associated with uncontrolled diabetes, obesity, and kidney disease?
Type V: hyperlipoproteinemias
