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  • Lab Values
  • Clinical Significance
  • Treatment Options
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Test Code 806

Test Details

Apolipoprotein E (apoE) Genotype Test

ApoE is a critical protein component of very low-density lipoprotein (VLDL) and chylomicrons. ApoE is important for:

  • Cholesterol absorption from the intestine
  • Uptake of triglyceride-rich lipoproteins by the liver
  •  The intended use of apoE genetic testing is as an aid in the selection of optimal cholesterol lowering protocols by the healthcare provider. The genetic test identifies individuals with altered lipid transport. Depending on the apoE genotype, cholesterollowering dietary interventions are very eff ective in these individuals, so determination of the genotype allows the physician to select the most eff icacious treatment regimen for the patient for lowering low density lipoprotein cholesterol and reducing heart disease risk.

 

The APOE gene has three common alleles (E2, E3, E4) that encode for three protein isoforms (E2, E3, E4). ApoE3 is the most common form of apoE. Population frequencies for these apoE alleles are:

  • E2 (15%)
  • E3 (65%)
  • E4 (20%)

Methodology

Real time polymerase chain reaction (PCR)

Patient Preparation

None

Preferred Specimen

1.0 mL whole blood collected in EDTA (Lavender Top)

Transport Temperature

Refrigerated (ship on frozen cold packs)

Stability

Refrigerated: 15 days

Lab Values

Lab Values

Apolipoprotein E (apoE) Genotype Test

  • E3/E3
  • E2/E2, E2/E3
  • E4/E4, E3/E4
  • E2/E4
Test Details
Clinical Significance

Clinical Significance

Apolipoprotein E (apoE) Genotype Test

E3/E3
Most common genotype; associated with:1-2

  • Decreased uptake of cholesterol by the liver
  • Lower total cholesterol and LDL-C

 

E2/E2, E2/E3
Associated with:1-2

  • Lower LDL-C levels than the common E3/E3 genotype
  • Lower total cholesterol and LDL-CV

 

E4/E4, E3/E4
Associated with higher LDL-C levels than the common E3/E3 genotype. Also associated with increased:1-2

  • Cholesterol absorption in the intestine
  • Uptake of intestinal cholesterol by the liver
  • Total cholesterol and LDL-C

References:

  1. Wilson PWF, Myers RH, Larson MG, Ordovas JM, Wolf PA, Schaefer EJ. Apolipoprotein E alleles, dyslipidemia, and coronary heart disease: the Framingham Off spring Study. JAMA. 1994;272(21):1666-1671.
  2. Bennet AM, Di Angelantonio E, Ye Z, et al. Association of apolipoprotein E genotypes with lipid levels and coronary risk. JAMA. 2007;298(11):1300-1311.
Lab Values
Treatment Options

Treatment Options

Apolipoprotein E (apoE) Genotype Test

E3/E3
If LDL-C or non-HDL-C lowering is needed, in addition to lifestyle change, statin therapy is recommended

 

E2/E2, E2/E3
If LDL-C or non-HDL-C lowering is needed, in addition to lifestyle change, statin therapy is recommended

 

E4/E4, E3/E4
If LDL-C or non-HDL-C lowering is needed, in addition to lifestyle change, combination therapy with statin and ezetimibe is recommended

 

E2/E4
If LDL-C or non-HDL-C lowering is needed, in addition to lifestyle change, statin therapy is recommended

Clinical Significance