CLS Diagnosis & Classification of Dyslipidemia 3 — Questions and Answers
Question 1: A 42-year-old woman has LDL-C of 210 mg/dL, tendon xanthomas, and her father died of MI at age 48. The Dutch Lipid Clinic Network score would classify her as:
- Possible FH
- Probable FH
- Definite FH (Correct answer)
- Unlikely FH
Correct answer: Definite FH
Tendon xanthomas alone yield 6 points, placing her at ≥8 points for definite FH in the Dutch Lipid Clinic Network scoring system.
Question 2: Which finding on a fasting lipid panel best indicates the presence of chylomicrons?
- LDL-C below detectable limits by Friedewald
- Plasma that remains turbid after refrigeration (Correct answer)
- Total cholesterol disproportionately high vs. TG
- HDL-C below 20 mg/dL
Correct answer: Plasma that remains turbid after refrigeration
Chylomicrons float to form a creamy supernatant upon refrigeration overnight, distinguishing them from VLDL which keeps the infranatant turbid.
Question 3: A patient with metabolic syndrome shows TG 200 mg/dL, HDL 38 mg/dL, and small dense LDL particles. This pattern is referred to as:
- Familial combined hyperlipidemia
- Atherogenic dyslipidemia triad (Correct answer)
- Isolated hypertriglyceridemia
- Polygenic hypercholesterolemia
Correct answer: Atherogenic dyslipidemia triad
The atherogenic dyslipidemia triad—elevated TG, low HDL, and small dense LDL—is a hallmark of insulin resistance and metabolic syndrome.
Question 4: Lp(a) levels are primarily determined by:
- Dietary fat intake
- LPA gene copy number variation (kringle IV type 2 repeats) (Correct answer)
- Statin use
- Hepatic PCSK9 expression
Correct answer: LPA gene copy number variation (kringle IV type 2 repeats)
Lp(a) concentrations are 70–90% genetically determined by the number of kringle IV type 2 repeats in the LPA gene, with shorter isoforms producing higher Lp(a) levels.
Question 5: In the ACC/AHA 2018 guidelines, which LDL-C threshold triggers consideration of additional risk-enhancing factors for statin initiation in primary prevention?
- ≥100 mg/dL
- ≥130 mg/dL (Correct answer)
- ≥160 mg/dL
- ≥190 mg/dL
Correct answer: ≥130 mg/dL
For intermediate-risk patients (7.5–20% 10-year ASCVD risk), an LDL-C ≥70 mg/dL is addressed, but primary prevention guidance focuses the 130 mg/dL threshold for discussion of risk enhancers.
Question 6: Which lipoprotein is measured directly in the NMR-based advanced lipid panel that is NOT routinely captured in a standard fasting panel?
- VLDL particle number
- LDL particle number (LDL-P) (Correct answer)
- Chylomicron remnants
- HDL3 subfraction
Correct answer: LDL particle number (LDL-P)
NMR spectroscopy directly quantifies LDL particle number (LDL-P), which can diverge from LDL-C and may better predict cardiovascular risk in certain patients.
Question 7: A patient with sitosterolemia would most likely present with:
- Markedly elevated plasma plant sterol levels with xanthomas despite normal LDL-C (Correct answer)
- Isolated severe hypertriglyceridemia with eruptive xanthomas
- Absent apolipoprotein B in plasma
- Very high HDL-C with corneal opacities
Correct answer: Markedly elevated plasma plant sterol levels with xanthomas despite normal LDL-C
Sitosterolemia (ABCG5/ABCG8 mutations) causes intestinal hyperabsorption of plant sterols, leading to xanthomas and atherosclerosis often with near-normal or mildly elevated LDL-C.
CLS Diagnosis & Classification of Dyslipidemia 3
A 42-year-old woman has LDL-C of 210 mg/dL, tendon xanthomas, and her father died of MI at age 48.
The Dutch Lipid Clinic Network score would classify her as: