Lipoprotein and ataxia

[Miracoli]

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A 10 years old male presents with failure to thrive, stools that are pale, bulky, and foul smelling, and night blindness. Physical exam shows absent Deep tendon reflexes, poor vision, wide gait ataxia, and generalized weakness. Fundoscopy exam shows bilateral retinal degeneration. Peripheral smear shows acanthocytosis. Lab studies also show low serum total cholesterol concentration. Which of the following lipoproteins would be in normal concentration in this patient?
a) HDL
b) VLDL
c) LDL
d) IDL
e) Lp(a)

 

[ArmyTiger]

A 10 years old male presents with failure to thrive, stools that are pale, bulky, and foul smelling, and night blindness. Physical exam shows absent Deep tendon reflexes, poor vision, wide gait ataxia, and generalized weakness. Fundoscopy exam shows bilateral retinal degeneration. Peripheral smear shows acanthocytosis. Lab studies also show low serum total cholesterol concentration. Which of the following lipoproteins would be in normal concentration in this patient?
a) HDL
b) VLDL
c) LDL
d) IDL
e) Lp(a)

Answer is e), correct? Sounds like abetalipoproteinemia, with a bunch of signs related to the inability to absorb vitamin A.

 

[Fatalis]

E, all others are low in this disease

 

[Miracoli]

why Lp(a) is not low in this pt?

 

[ArmyTiger]

why Lp(a) is not low in this pt?

Abnormality is in the B lipoprotein gene (which makes ApoB-100 and ApoB-48). That makes chylomicrons, VLDL, LDL, and IDL low (no structural proteins to make them). You also get hypocholesterolemia (unsure of the mechanism), so HDL will be low. Lp(a) production is independent of all of those factors.

 

[Miracoli]

But does HDL has apoB?

 

[ArmyTiger]

But does HDL has apoB?

No, but its main role is cholesterol transport. Low cholesterol, low HDL (I'm pretty sure)

 

[Miracoli]

-Lip(a) also has apoB100
-there is decreased HDL3 but high HDL2
-the apoB gene is normal but the MTTP gene is mutated--> no Microsomal triglyceride transfer protein, which is required for the assembly and secretion of of apoB--> no VLDL, LDL,IDL& Lip(a)

 

[Fatalis]

-there is decreased HDL3 but high HDL2

I LOL'd at this...honestly man....

 

[Miracoli]

Lol! HDL is made denovo(not derived from LDL or VLDL) from the liver. There are different types of HDL(not that you have to know them) so if you have low LDL some will be high and others will be low.

 

[purplelife]

what's Lp(a)? = apolipoprotein A1?

I'm having hard time remembering major apolipoprotein and Lipoprotein functions. 🙁