- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: The ADRB2 gene encodes for the beta-2-adrenergic receptors expressed on many cell types including cells of the airways, the vascular and immune systems, and fat cells. Binding and release of epinephrine and norepinephrine, the natural ligands on the receptor, regulates cardiac, pulmonary, vascular, immunologic, and metabolic functions. The beta-2-adrenergic receptors are the targets of beta-agonists drugs. ADRB2 appears to be one of the multiple genetic players in asthma, vascular disease, obesity and drug response.
Genetics: At least twelve haplotypes of the ADRB2 gene have been described using 13 polymorphic sites. The three haplotypes (Gly16-Glu27, Arg16-Gln27 and Gly16-Gln27) are the most common. Arg16 and Gln27 are in strong linkage disequilibrium. Arg16 has been found associated with Glu27 in less than 0.5 percent of chromosomes.
Mutations Tested: Arg16Gly (c.46A>G), Gln27Glu (c.79C>G) and the three main haplotypes Gly16-Glu27, Arg16-Gln27, and Gly16-Gln27.
Methodology: PCR and fluorescence analysis by haplotyping hybridization probes. In addition to genotyping each mutation tested, this test directly establishes the haplotype (whether or not the two mutations are found on the same or different chromosomes).
Limitations: Mutations and haplotypes situated outside of the studied area of the gene are not analyzed. Other and non-described mutations and haplotypes can be revealed by the assay. Medical significance of the polymorphisms and their haplotypes in the different diseases (asthma, obesity, hypertension, and drug response) are continually being investigated. Diagnostic errors can occur due to rare sequence variations.
Analytical Sensitivity: The assay determines the haplotypes of approximately 99 percent of chromosomes.
This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.
|Component Test Code*||Component Chart Name||LOINC|
|0051289||Beta-2-Adrenergic Receptor Haplotyping|
|2001291||Beta-2-Adrenergic Receptor Specimen|