Familial Adenomatous Polyposis (APC) Deletion/Duplication
2004920
Ordering Recommendation
Diagnostic testing for familial adenomatous polyposis. Predictive testing for familial adenomatous polyposis.
Mnemonic
APC DELDUP
Methodology
Polymerase Chain Reaction/Multiplex Ligation-dependent Probe Amplification
Performed
Varies
Reported
Within 14 days  
New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
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
   
Interpretive Data
Background Information for Familial Adenomatous Polyposis (APC) Deletion/Duplication:
Characteristics of APC-associated Polyposis:

Familial Adenomatous Polyposis (FAP):Development of hundreds to thousands of adenomatous colonic polyps beginning in early adolescence; lifetime risk for cancer is 100 percent. Additional findings may include dental anomalies, polyps of the gastric fundus and duodenum, and congenital hypertrophy of the retinal pigment epithelium (CHRPE).
Attenuated FAP: Fewer colonic adenomatous polyps (average of 30), which are more proximally located and cancer generally occurs at a later age; lifetime risk for cancer is 70 percent.
Gardner syndrome: Multiple colonic adenomatous polyps along with osteomas, desmoid tumors, and soft tissue tumors.
Incidence:
Less than 1 percent of colorectal cancer cases.
Inheritance:
Autosomal dominant.
Penetrance:
Greater than 99 percent in untreated individuals with classic FAP.
Cause:
Pathogenic APC mutations.
Clinical Sensitivity:
Approximately 8-12 percent for classic FAP.
Methodology:
Multiplex ligation-dependent probe amplification (MLPA) to detect large APC coding region deletions and duplications.
Analytical Sensitivity and Specificity of MLPA:
99percent.
Limitations
: Diagnostic errors can occur due to rare sequence variations. Single base pair substitutions, small deletions/duplications, regulatory region mutations, and deep intronic mutations will not be detected. Deletion/duplication breakpoints will not be determined. Mutations in genes other than APC will not be detected.





See Compliance Statement C: www.aruplab.com/CS
Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test; however, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
 
Note
 
CPT Code(s)
81203
Components
Component Test Code*Component Chart Name
2004921FAP (APC) Del/Dup Specimen
2004922FAP (APC) Del/Dup Interpretation
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • APC-Associated Polyposis
  • Attenuated FAP
  • Gardner Syndrome
  • Turcot Syndrome