Apolipoprotein E (APOE) 2 Mutations, Cardiovascular Risk
0055566
 
Ordering Recommendation
Use to detect APOE mutations in individuals with a suspicion of type III hyperlipoproteinemia (familial hyperlipoproteinemia).
Mnemonic
APO E
Methodology
Polymerase Chain Reaction/Fluorescence Monitoring
Performed
Mon, Thu
Reported
2-7 days
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
 
Collect
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).  
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL)  
Storage/Transport Temperature
Refrigerated.  
Unacceptable Conditions
 
Remarks
 
Stability
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable  
Reference Interval
Homozygous apo e3 (e3/e3): This genotype is the most common (normal) genotype.
Interpretive Data
Background Information for Apolipoprotein E (APOE) 2 Mutations, Cardiovascular Risk
Characteristics:
Hyperlipoproteinemia III (HPL III) is characterized by increased cholesterol and triglyceride levels, presence of B-VLDL, xanthomas, and premature vascular disease including coronary heart disease (CHD) and peripheral artery disease.
Incidence of HPL III:
Approximately 1 in 5,000.
Inheritance:
Autosomal recessive.
Penetrance:
1 to 5 percent of individuals homozygous for the E2 allele and 26 percent of those heterozygous for both E2 and familial hypercholesterolemia will develop symptoms.
Cause:
The E2 isoform binds the lipoprotein receptors with only 2 percent of the affinity of E3 and E4 resulting in impaired clearance of chylomicron and VLDL remnants and increased plasma cholesterol and triglyceride levels.
Mutations Tested:
E2, E3 (normal) and E4 alleles of the apolipoprotein E gene.
Clinical Sensitivity:
About 5 percent of individuals with premature CHD are homozygous for E2.
Methodology:
Polymerase chain reaction (PCR) and fluorescence monitoring using hybridization probes.
Analytical Sensitivity and Specificity:
99 percent.
Limitations:
Rare isoforms of APOE will not be detected. If rare alleles are suspected, phenotyping by isoelectric focusing may be indicated. Diagnostic errors can occur due to rare sequence variations.

This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS
Note
This test is for cardiovascular risk assessment only and must not be ordered for assessing Alzheimer disease in a demented patient. Athena Neurosciences, Inc. is the exclusive licensee of U.S. Patent No. 5,508,167 for the Alzheimer risk assessment.

This test is not recommended for nonsymptomatic patients under 18 years of age.
CPT Code(s)
81401

Components
Component Test Code*Component Chart Name
0055566Apo E for Cardiovascular Risk
2001298APO E Specimen
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, contact interface support at interface.support@aruplab.com.
Cross References
  • APO E Cardiac Risk
  • ApoLipoprotein E Genotype