Alternate test when clinical/family history is classic for HHT. Test does not detect large duplications/deletions.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Recurrent nosebleeds, telangiectases (mouth, face, hands, GI tract), arteriovenous malformations (lung, brain, liver, spine).
Inheritance: Autosomal dominant
Penetrance: Approaches 100 percent by age 40.
Cause: Pathogenic variants in the endoglin (ENG), activin A receptor type II-like 1 (ACVRL1 or ALK1), SMAD4 or other unidentified gene(s).
Clinical Sensitivity: Approximately 75 percent
Methodology: Bidirectional sequencing of the coding regions and intron-exon boundaries of ENG and ACVRL1, the 5' untranslated region of ENG, and a region of ACVRL1 intron 9 encompassing the CT-rich variant hotspot region.
Analytic Sensitivity and Specificity: 99 percent
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region and intronic mutations, large deletions/duplications, and mutations in genes other than ENG and ACVRL1 will not be detected.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2001357||HHT, Sequencing - Specimen|
- ACVRL1 and ENG sequencing
- HHT sequencing