| Interpretive Data: |
Background Information for Familial Adenomatous Polyposis (APC) Sequencing:
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.
Causes: Pathogenic APC allelic variations
Clinical Sensitivity: Approximately 90 percent for classic FAP and less than 30 percent for attenuated FAP.
Methodology: Bidirectional sequencing of the APC coding region and intron-exon boundaries.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Rare diagnostic errors can occur due to primer site mutations. Regulatory region mutations, deep intronic mutations, and large deletion/duplications will not be detected.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.
Refer to Statement C under Testing Information at http://www.aruplab.com.
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| CPT Code(s): |
83891 Isolation; 83898 x40 Amplification; 83904 x40 Sequencing; 83909 capillary electrophoresis; 83912 Interpretation and report - Additional CPT code modifiers may be required for procedures performed to test for oncologic or inherited disorders.
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Cross References: |
APC-Associated Polyposis (Familial Adenomatous Polyposis (APC) Sequencing)
, Attenuated FAP (Familial Adenomatous Polyposis (APC) Sequencing)
, Gardner Syndrome (Familial Adenomatous Polyposis (APC) Sequencing)
, Turcot Syndrome (Familial Adenomatous Polyposis (APC) Sequencing)
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