ARUP's Laboratory Test Directory

Juvenile Polyposis (SMAD4) Sequencing and Deletion/Duplication : 2001971
[ image for: Patient History for Juvenile Polyposis (JPS)/Hereditary Hemorrhagic Telangiectasia (HHT)]
Patient History for Juvenile Polyposis (JPS)/Hereditary Hemorrhagic Telangiectasia (HHT)
[ image for: Additional Technical Information]
Additional Technical Information


Mnemonic: SMAD4 FGA

Ordering Recommendation: Diagnostic testing for juvenile polyposis syndrome/ hereditary hemorrhagic telangiectasia. Predictive testing for juvenile polyposis syndrome/ hereditary hemorrhagic telangiectasia.
Methodology: Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification
Performed: Varies
Reported: Within 35 days
Specimen Required: Collect: Lavender (EDTA), pink (K2EDTA), or yellow (ACD solution A or B).

Specimen Preparation: Transport 3 mL whole blood. (Min: 2 mL)

Storage/Transport Temperature: Refrigerated.

Stability (collection to initiation of testing): Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Interpretive Data: Background Information for Juvenile Polyposis (SMAD4) Sequencing and 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 25 percent for JPS; unknown for JP/HHT.
Methodology: Bidirectional sequencing of the entire SMAD4 coding region and intron-exon boundaries. Multiplex ligation-dependent probe amplification (MLPA) to detect large SMAD4 coding region deletions/duplications.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Rare diagnostic errors can occur due to primer or probe site mutations. Breakpoints for large deletions/duplications will not be determined.



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
CPT Code(s): 81479 (2)
Cross References: SMAD4 (Juvenile Polyposis (SMAD4) Sequencing and Deletion/Duplication)