- 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: Multifocal, randomly distributed, capillary malformations (CM) that may be associated with a fast-flow lesion (arteriovenous malformations [AVM] or arteriovenous fistula). Fast-flow lesions in the skin, muscle, bone, internal organs or brain can cause life-threatening complications such as bleeding, congestive heart failure, or neurological consequences. Capillary malformation-arteriovenous malformation syndrome (CM-AVM) and Parkes-Weber syndrome may be caused by RASA1 mutations.
Incidence: Estimated at 1 in 100,000.
Inheritance: Autosomal dominant; approximately one-third are de novo.
Penetrance: 90-95 percent.
Cause: Pathogenic RASA1 gene mutations.
Clinical Sensitivity: 75 percent for CM-AVM based on a single study; unknown for other conditions.
Methodology: Bidirectional sequencing of all coding regions and intron-exon boundaries of the RASA1 gene;Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large RASA1 deletions/duplications.
Analytical Specificity and Sensitivity: 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 16 and 20 may or may not be detected depending on the breakpoint locations. The breakpoints of large deletions/duplications will not be determined.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2007853||RASA1 Seq, Del/Dup Specimen|
|2007854||RASA1 Seq, Del/Dup Interp|
- Capillary Malformation-Arteriovenous Malformation Syndrome
- Parkes-Weber Syndrome
- RASA1 sequencing and deletion/duplication assay