Diagnostic and predictive testing for juvenile polyposis syndrome.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 2 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Multiple juvenile (hamartomatous) polyps in the stomach, small intestine, colon, and rectum. Risk for colon cancer is 20 percent by age 35 and 70 percent by age 60.
Incidence: 1 in 16,000 to 100,000 individuals.
Inheritance: Autosomal dominant.
Penetrance: Greater than 90 percent for polyp development.
Cause: Pathogenic BMPR1A and SMAD4 mutations.
Clinical Sensitivity: 20-25 percent.
Methodology: Bidirectional sequencing of the entire BMPR1A coding region and intron-exon boundaries. Multiplex ligation-dependent probe amplification (MLPA) to detect large BMPR1A coding region deletions and duplications.
Analytical Sensitivity & Specificity for Sequencing and MLPA: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations and deep intronic mutations will not be detected. Large deletions/duplications of exons 7 and 8 may not be detected. The breakpoints of large deletions/duplications will not be determined. Mutations in genes other than BMPR1A are not evaluated.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2004993||JPS (BMPR1A) Seq, Del/Dup Specimen|
|2004994||JPS (BMPR1A) Seq, Del/Dup Interpretation|
- BMPR1A sequencing and deletion/duplicatoin