Reference Interval:
By report
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| Interpretive Data: |
Background Information for Juvenile Polyposis (SMAD4) Deletion/Duplication:
Characteristics of Juvenile Polyposis Syndrome (JPS): Gastrointestinal (GI) bleeding, multiple hamartomatous polyps in the GI tract, increased risk for GI carcinoma.
Characteristics of JP/Hereditary Hemorrhagic Telangiectasia (HHT): Recurrent nosebleeds, telangiectases (mouth, face, hands, GI tract), arteriovenous malformations (lung, brain, liver, spine) and hamartomatous polyps in the GI tract.
Incidence: 1 in 16,000 to 1 in 100,000 for JPS; unknown for JP/HHT.
Inheritance: Autosomal dominant; de novo mutations occur in 25 percent of JPS.
Penetrance: Suspected to be greater than 90 percent for JPS.
Cause for JPS: Mutations in SMAD4, BMPR1A and other unknown genes.
Cause for JP/HHT: Mutations in SMAD4.
Clinical Sensitivity: Approximately 10 percent for JPS; unknown for JP/HHT.
Methodology: Multiplex ligation-dependent probe amplification (MLPA) to detect large SMAD4 coding region deletions/duplications.
Analytical Sensitivity and Specificity: 90 and 99 percent, respectively.
Limitations: Rare diagnostic errors can occur due to probe site mutations. Breakpoints for large deletions/duplications will not be determined. SMAD4 base pair substitutions, small deletions/duplications, deep intronic, and regulatory region mutations 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; 83896 Nucleic acid probes; 83898 Amplification; 83914 Extension; 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: |
SMAD4 (Juvenile Polyposis (SMAD4) Deletion/Duplication)
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![[ image for: Patient History for Juvenile Polyposis (JPS)/Hereditary Hemorrhagic Telangiectasia (HHT)]](icon_37.jpg){kind=icon}