Acceptable test when clinical/family history is classic for HHT.
- 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: Recurrent nosebleeds, telangiectases (mouth, face, hands, GI tract), and arteriovenous malformations (lung, brain, liver, spine).
Inheritance: Autosomal dominant.
Penetrance: Approaches 100 percent by age 40.
Cause: Pathogenic mutations in ENG, ACVRL1/ALK1, SMAD4, BMP9/GDF2 or other unidentified gene(s).
Genes Tested:ENG and ACVRL1
Clinical Sensitivity: Approximately 85 percent
Methodology: Bidirectional sequencing and multiplex ligation-dependent probe amplification (MLPA) of the entire coding regions and intron-exon boundaries of ENG and ACVRL1, as well as the 5' untranslated region of ENG.
Analytic Sensitivity: 99 percent for sequencing and 90 percent for MLPA.
Analytic Specificity: 99 percent for sequencing and 98 percent for MLPA.
Limitations: Diagnostic errors can occur due to rare sequence variations. The breakpoints of large deletions/duplication cannot be determined. Regulatory region, intronic mutations, and mutations in genes other than ENG and ACVRL1 will not be detected.
|Component Test Code*||Component Chart Name||LOINC|
|0051350||HHT, Sequencing and Deletion/Duplication|
|2001355||HHT, Seq-Del/Dup - Specimen|
- Activin A Receptor, Type II-Like I
- ACVRL1 Gene; ALK1 Gene
- Arteriovenous Malformations
- AVM genetic testing
- HHT molecular testing