Cure HHT strongly encourages individuals and families to arrange genetic testing through a health care provider who understands all of the complexities and limitations of genetic testing for HHT. In most cases this means having an appointment with a medical geneticist or genetic counselor.
Important Note: Genetic testing technologies have advanced over time, and will continue to improve in the future. People from HHT families in which a mutation has not been identified, or was considered to be of uncertain significance, should periodically check back with the testing laboratory or a genetics professional to find out if additional analysis would be useful.
Why would genetic testing for HHT be done?
Genetic testing for HHT is done for several reasons.
- To establish or confirm a diagnosis in someone who does not meet the required clinical criteria for HHT but is suspected of being affected.
- To identify the affected gene in a person who is known to have HHT, in order to accurately test other family members
- To test for the presence or absence of a mutation on an HHT-associated gene in a person who does not show symptoms of HHT but has a close relative (usually a parent or sibling) who has been genetically diagnosed. The presence of the family HHT-causing mutation would prove HHT, while its absence would rule it out.
Unless HHT is ruled out by genetic testing, all children of a parent with HHT should be screened for brain and lung AVMs. For young children, these procedures require sedatives, or general anesthesia, but they are critical to establishing proper diagnosis and care. If an HHT mutation has already been identified in a family, genetic testing of at-risk family members for the known mutation will identify which family members have HHT and therefore need to be screened for internal AVMs.
What are possible results from genetic testing for HHT?
When the initial family member is tested to identify a family’s HHT-causing gene mutation, there are three possible results:
- Positive for a “pathogenic” (HHT- causing) mutation; the laboratory found a mutation (change in DNA) in one of the HHT a genes, and the mutation is thought to cause HHT. This person does have HHT and their DNA can be used to help identify other affected family members.
- Negative. In most scenarios, this means a person does not have HHT. Very rarely, a negative result indicates that a person has HHT, but the affected gene is still unknown.
- Variant of Uncertain Significance. This means a genetic variant is detected in one of the HHT genes, but it is not possible to confirm that it is the cause of HHT.
When additional family members are tested for the specific HHT-causing mutation already identified in the initially tested family member, there are two possible results.
- Positive. This result means that the family HHT gene mutation is present, and that the tested person has HHT.
- Negative. This result means that the family HHT gene mutation is not present, and that the person tested did not inherit HHT.
I have HHT and want to know if my children have HHT. What do I do?
A child born to a parent with HHT has a 50% chance of inheriting the disorder, and establishing a diagnosis at a young age can be crucial to improving quality of life.
You or another affected family member should seek genetic testing to identify the HHT-associated gene.
- HHT families share a “private” affected gene, so if one person is genetically diagnosed, other family members can be diagnosed by comparing DNA.
- The test ordered to look for a pre-determined, family mutation has several names, including “Site Specific”, “Familial Mutation” and “Targeted Sequencing”.
HHT does not skip generations.
- If a child tests negative for the family-affected gene, that child does not require further evaluation and cannot pass HHT on to future generations.
- Individuals who test positive should keep their test results so other family members can be properly diagnosed, and should also be screened for manifestations such as AVMs in the brain and lungs.
How do I go about arranging for genetic testing?
When it comes to genetic testing, you and your family have several options.
- Through an HHT Center of Excellence.
- Through a medical genetics clinic or genetic counselor.
- Through a primary care provider or specialty physician.
We encourage families to visit an HHT Center of Excellence if they are able, as they provide the most comprehensive expert care. If you are not able to travel to a Center, then most primary care providers will be able to order the test, though they may want to consult with an HHT Center. A physician may also refer you to a lab that offers testing for HHT and employs employ genetic counselors who can assist care providers with test ordering, facilitate sample collection and shipping, and help with interpretation of results.
If the family cannot travel to an HHT Center, and their primary healthcare provider is unable to order HHT genetic testing, a referral to a medical geneticist or genetic counselor may be needed.
- Find genetic counselors in your region through the National Society of Genetic Counselors (nsgc.org)
- or find Medical Geneticists, Genetic Counselors and genetics clinics through geneclinics.org.
How much does genetic testing for HHT cost and will my insurance pay for it?
The cost of genetic testing varies.
- The initial test to determine the affected family gene can cost $2,000 or more.
- Once the family gene is identified, a test for another family member typically costs $300-$400.
Most insurance policies cover genetic testing as a standard lab procedure. Pre-authorization is often required, but physicians or genetic counselors who are familiar with genetic testing are also familiar with pre-authorization and will be able to help you through the process. It is rare for an insurance policy to specifically exclude genetic testing, but labs are equipped to assist patients in verifying their coverage.
Does testing positive for a mutation in an HHT gene lead to insurance discrimination?
The short answer is no, but it’s normal to feel concerned or anxious that testing will prevent you and our family from obtaining health insurance, or to worry that you will be charged more than other people.
- The 2008 federal Genetic Information Nondiscrimination Act (GINA) prohibits a health insurer or employer from discriminating against an individual based on that person’s risk for disease as determined by a genetic test.
- Legally, health insurers cannot use genetic test results as a basis for determining eligibility or premiums, and employers cannot use them as a basis for hiring, firing or other terms of employment.
- Most states have additional laws prohibiting various forms of discrimination based on genetic test results.
These laws do not currently extend to life insurance – companies are permitted to consider genetic test results when reviewing an applicant for life insurance.