NBME 20 Lipoprotein lipase (NBME Answers)

Retired NBME Answer Explanations

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Retired NBME 20 Answers

nbme20/Block 4/Question#48 (reveal difficulty score)
A 24-year-old man comes to the emergency ...
Lipoprotein lipase 🔍 / 📺 / 🌳 / 📖
tags: biochem repeat

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submitted by ∗hayayah(1212)

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Pt. has Familial dyslipidemias. Type I—Hyperchylomicronemia.

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estefanyargueta Lipoprotein lipase: degradation of TGs circulating in chylomicrons and VLDLs. +2

breis FA 2019 pg 94 +4

lulumomovicky Hyperchylomicronemia can be due to LPL or Apolipoprotein C-II deficiencies --> leading to high levels of QM, TG, and Cholesterol +

http://nlaresourcecenter.lipidjournal.com/Content/PDFs/Tables/1.pdf

type 1 hyperchylomicronemia ( pancreatitis and TG's in the 1000's.)

+3/- medblues(2)

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submitted by blanee1380(4)

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Very large increase in TGs causes pancreatitis.
Deficiencies in:

Apo B-100: Type II familial hypercholesterolemia, increases mostly LDL which increases cholesterol

Apo E: Decreased remnant uptake, which increases mostly chylomicrons and VLDL, but it's milder so no pancreatitis.

HSL: deficiency would decrease TGs, not increase

LDL receptor: Type II hypercholesterolemia also

So lipoprotein lipase deficiency is the anser, which causes large increase in chylomicrons and TGs, leading to pancreatitis and has a creamy layer in supernatant.

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submitted by ∗chj7(11)

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Side note for those of you who hate familial dyslipidemias: don't usually watch dirty USMLE videos but I couldn't keep the familial dyslipidemias straight in my head and someone on reddit recommended his video on this. Personally found it really helped.

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submitted by ∗pg32(218)

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Can anyone explain why the lipase concentration is so high if there is an issue with LPL in hyperchylomicronemia?

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garima due to pancreatitis +7

neovanilla ELI5? +

suckitnbme @neovanilla Type 1-hyperchylomicronemia has increased risk of pancreatitis +

makingstrides I don't understand why this isn't hypertriglyceridemia because this also causes acute pancreatitis. Maybe because overproduction of VLDL isn't an answer? +

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