Diseases Of Lipid Metabolism Flashcards
Lipid profile testing
. Blood collected after 12 hr fast
Total cholesterol diserable, borderline, and high numbers
. Desirable: <200
. Border: 200-239
. High: > 240
TAG desirable, borderline, high, and very high levels
. Normal: <150
. Border: 150-199
. High: 200-499
. Very high >500
HDL low level and high level
. Low: <40
. High: >60
LDL normal, near normal, borderline high, high, and very high values
. Normal: <100 . Near normal: 100-129 . Borderline high: 130-159 . High: 160-189 . Very high: >190
Friedewald equation
. LDL = TC - HDL- (TG/5)
. Only valid w/ patient fasting and if lipids are reported in mg/dL units and TG< 400
Specialized tests that may be included w/ lipid profile
. Direct LDL . VLDL . non-HDL . Apo levels . APo E genotyping . lipoprotein a (LAL-like lipoprotein particle) . Lipoprotein particle size . Lipoprotein electrophoresis
Primary lipid disorders
. Uncommon
. Suspected if: physical manifestations of hyperlipidemia, early athlerosclerotic heart disease, family history, extremely high blood lipid levels
Familial combined hyperlipidemia
. Most common hyperlipidemia (1% pop.)
. Mild-moderate in severity
. Hepatic overproduction of VLDL and possibly limits VLDL clearance from blood
. May be due to overproduction of apo B-100
. Mild-moderate elevation of TAGs and/or cholesterol
. Diagnosis challenging
Familial hypercholesterolemia
. Mutation in gene coding for LDL receptor or genes for apo B-100 and PCSK-9
. Could effect LDLR synthesis, transport to cell surface, B 100 binding, endocytosis, or recycling
. LDL not cleared from blood and severe hypercholestermia ensues
. Autosomal dominant w/ gene-dosage effect (heterozygous has symptoms but not as severe as homozygous
. Treat w/ statins, lifestyle, or plasma spheres is to remove cholesterol from blood
Tangier disease
. Autosomal
. Mutation in gene coding for ABCA1 cholesterol transporter
. Accumulation of cholesterol in various organs and tissues (tonsils common)
. Low blood HDL
. Early atherosclerotic disease common
Sitosterolemia
. Abnormal accumulation of plant sterols and mildly elevated cholesterol in blood
. Gene mutation in ABCG5/8 or NPC1L1
Abetalipoproteinemia
. Autosomal recessive condition assoc. w/ mutation in gene coding for microsomal triglyceride transfer protein (MTP)
Apolipoprotein C-II and familial hyperchylomicronemia deficiencies
. Assoc. w/ severe hypertriglyceremia
. Mutation in genes coding for lipoprotein lipase or apo C-II
. Symptoms in childhood: colic, abdominal pain, failure to thrive
. Symptoms as adult: pancreatitis, heart disease from hyperlipidemia
Secondary lipid disorders
. Acquired
. Common causes: DM, pregnancy, hypothyroidism, kidney/liver disease, excess alcohol, meds
. Treatment: treat underlying cause