Genetic testing is common procedure used across many medical fields, including diagnosis and treatment of inherited diseases like HHT. The test analyzes the DNA (genetic material carried in cells) in small samples of blood or saliva to identify similarities, differences or anomalies. Genetic testing for HHT establishes the HHT-associated genes within a family so that other members of the same family can be accurately diagnosed.
- 95% of people who meet the clinical diagnostic criteria for HHT show a genetic mutation in a test of the ENG (HHT1) and ACVRL1 (HHT2)
- 2% of clinically diagnosed individuals test positive for SMAD4
- About 3% will not test positive for a known HHT gene.
Though a handful of people around the world have tested for HHT with mutations on the BMP9/GDF2, the diagnosis is so rare (<<1%) that it is not a part of the routine test.