Case 5 Flashcards
What type of disorder is heterozygous hypercholesterolemia?
autosomal codominant
What is the average level of cholesterol in heterozygous hypercholesterolemia patients?
300 to 600mg
what symptoms are associated with hypercholesterolemia (FH)?
- tendinous and tuberous xanthomas in skin
- Arcus in cornea
cholesterol elevation is associated with what?
increase in LDL-C
- can synthesize intracellular cholesterol but lack in their receptors
What are the classes of defects in LDL receptors in FH?
- Class 1: no LDL receptor
- Class 2: membrane protein not transported to golgi and degraded
- Class 3: LDL receptor can’t bind to LDL
- Class 4: LDL receptor cannot internalize LDL and transport it to golgi
- Class 5: LDL receptors don’t recycle
Which type of mutation is the most common?
Class 2 mutation
How do cells obtain cholesterol when receptors are lacking?
make intracellular cholesterol to compensate
In FH heterozygotes, how do we reduce cholesterol?
by using HMG-CoA reductase inhibitors (statins)
How do statins decrease cholesterol levels?
by increasing LDL receptors (in liver mainly) to remove LDL from the circulation
How do we treat FH homozygotes?
LDL pheresis 4
how high are TAG levels in borderline, high, and very high triglyceridemia?
- borderline: 150-200
- high: 200 - 500
- very high: more than 500
what are the causes of hypertriglyceridemia?
- familial hypertriglyceridemia
- secondary to hormonal abnormalities, diabetes, or nephrosis
how does diabetes cause hypertriglyceridemia?
shunting of glucose pathway into pentose pathway, leading to increased fatty acid synthesis
how does renal failure cause hypertriglyceridemia?
depresses removal of large-molecular-weight constituents like TAG
What hormones can affect TAG levels and how?
- epinephrine & norepinephrine, growth hormone, ACTH, thyrotropin, and glucagon
- by triggering production of hormone sensitive lipase located on adipose tissue
