Next-Generation Sequencing and Deletion/Duplication Analysis of RASA1 and EPHB4 for CM-AVM / Parkes Weber Syndrome (RASA-NG)
Information for Ordering
Acceptable Specimen Types
- Fresh blood sample: 3–6 mL EDTA; no time limitations associated with receipt
- Saliva: OGD-575 DNA Genotek collection kit; kits are provided upon request
- DNA extracted from lymphocyte cells: minimum volume of 25 µL containing 3 µg of DNA; A260/A280 ratio ≥1.8; must be extracted in a CLIA-certified or equivalent laboratory
Turnaround Time
- Blood, saliva, or DNA: Average of 30 working days
Price, CPT Codes, and Z Code
- Institutional/self-pay price: $1,000 USD
- CPT codes: 81479 × 2
- Z code: ZB6AB
Candidates for Testing
Patients with clinical features suggestive of Capillary Malformation–Arteriovenous Malformation (CM-AVM) syndrome or Parkes Weber syndrome.
Specimen Shipping and Handling
Please refer to the specimen requirements listed above.
Blood, saliva, and extracted DNA specimens should be shipped at room temperature.
Specimens must be packaged to prevent breakage. Absorbent material must be included to contain liquids if breakage occurs. Specimens must also be shipped in double watertight containers, such as a specimen pouch placed inside the shipping company's diagnostic envelope.
To request a collection kit, please complete the Collection Kit Request Form.
Before shipping a specimen, please contact the UAB Medical Genomics Laboratory by email at medgenomics@uabmc.edu or by phone at 205-934-5562. Please provide the specimen type, shipment date, and package tracking number so the laboratory can help ensure proper and timely receipt.
Required Forms
About
Disorder Background
Capillary Malformation–Arteriovenous Malformation syndrome (CM-AVM) is a vascular disorder characterized by capillary malformations and fast-flow vascular lesions, including arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs). Parkes Weber syndrome shares many clinical features with CM-AVM, including congenital capillary malformations associated with high-flow vascular anomalies.
Pathogenic variants in RASA1 are a well-established cause of CM-AVM syndrome and many cases of Parkes Weber syndrome. More recently, loss-of-function variants in EPHB4 have been shown to produce a similar phenotype. Because EPHB4 interacts with RASA1 within the EPHB4-RAS-ERK signaling pathway, both genes are included in this testing panel.
Test Description
The RASA1 and EPHB4 by NGS assay includes sequencing of both RASA1 and EPHB4, together with deletion/duplication analysis of RASA1. The assay utilizes a customized Agilent HaloPlex target enrichment system followed by paired-end Illumina sequencing. Each coding exon and approximately 50 base pairs of flanking intronic sequence are analyzed. The 5′ and 3′ untranslated regions are not included.
The average sequencing coverage is approximately 1,500×, with 93% of coding regions covered at ≥350× and 97% covered at ≥200×. This depth of coverage permits detection of low-level mosaicism to approximately 3%–5% variant allele fraction.
Variant and copy-number calls are generated using a validated bioinformatics pipeline capable of detecting single-nucleotide variants, insertions, deletions, frameshifts, and deletion/duplication events up to 112 base pairs.
View references for this testing.
For more information, test requisition forms, or collection kits, please contact the UAB Medical Genomics Laboratory at 205-934-5562 or medgenomics@uabmc.edu.