- 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), arteriovenous malformations (lung, brain, liver, spine).
Inheritance: Autosomal dominant.
Penetrance: Approaches 100 percent by age 40.
Cause: Mutations in endoglin (ENG), the activin A receptor type II-like 1 (ACVRL1 or ALK1), SMAD4 and other unidentified gene(s).
Clinical Sensitivity: Approximately 10 percent of HHT is caused by large deletions or duplications in either the ACVRL1 or ENG genes.
Methodology: Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large ENG and ACVRL1 deletions/duplications; oligonucleotide probes cover all ENG and ACVRL1 coding exons.
Analytical Sensitivity: 90 pecent
Analytical Specificity: 98 percent
Limitations: Diagnostic errors can occur due to rare sequence variations. Deletion/duplication breakpoints cannot be determined. Single base pair substitutions and small deletion/duplication mutations 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|
|0051387||HHT Deletion/Duplication Interpretation|
|2001354||HHT DELDUP Specimen|
- ACVRL1 and ENG Deletion/Duplication
- HHT (Hereditary Hemorrhagic Telangiectasia (ACVRL1 and ENG) Deletion/Duplication)
- HHT duplication/deletion assay