My parent has hATTR-PN. Do I need genetic testing?
Fact-checked by When a family member is diagnosed with hereditary transthyretin amyloidosis with polyneuropathy (hATTR-PN), it can raise questions for the entire family. Because hATTR-PN is an inherited condition, it can be passed from parent to child.
If you have a parent who has been diagnosed with hATTR-PN, your doctor may suggest that you undergo genetic testing for the condition. Learning more about what genetic testing for hATTR-PN involves and what the results could mean can help you make informed choices about your health and future planning.
How hATTR-PN is inherited
hATTR-PN is a rare disease caused by mutations in the TTR gene. The condition follows an autosomal dominant inheritance pattern, meaning a child only needs to inherit one mutated copy of the gene to be at risk of developing the disease.
If one parent carries a TTR variant, each child has a 50% chance of inheriting it. In rare cases, a parent may carry two mutated copies of the TTR gene, meaning all of their children would inherit a TTR mutation.
More than 140 TTR variants have been identified, and each may be associated with a different pattern of disease, including the age at which symptoms begin, the organs most affected, and how quickly the condition progresses. Knowing which variant runs in your family can help guide inherited amyloidosis family screening and inform decisions about monitoring for early signs of the disease.
When family members may consider genetic testing
In cases where there’s a family history of hATTR-PN, a doctor might recommend genetic testing for close relatives — parents, siblings, and children — of the diagnosed person.
Not everyone who inherits a TTR mutation will develop the disease. However, knowing that you carry a TTR mutation can help doctors monitor you for the earliest signs of the condition so treatment can begin as soon as possible if symptoms develop.
In some cases, genetic testing may also help identify TTR mutation carriers who already have subtle early symptoms of the disease that were previously attributed to other, more common health conditions. For these individuals, such testing may enable earlier diagnosis and treatment.
Even if you aren’t experiencing symptoms, a TTR mutation carrier test can provide clear information about your genetic risk and help guide family planning decisions. However, the timing of testing may depend on the specific TTR mutation, how severe the disease has been in affected relatives, and the age at which symptoms typically began.
In general, parents and siblings of someone with hATTR-PN may benefit more from genetic testing because, if they carry the mutation, they may be closer to the age when symptoms are likely to appear. By contrast, children who test positive may need monitoring for many years before symptoms develop, which can sometimes cause stress or anxiety.
Testing is typically done using a blood sample, saliva, or cheek swab, and results are often available within a few weeks.
What a positive or negative result may mean
A positive result means you carry the TTR mutation found in your family. It does not mean you currently have hATTR-PN or that symptoms are guaranteed to develop. Your level of risk depends on your specific mutation, geographic background, and age.
Even among people with the same mutation, the likelihood of developing symptoms can vary widely. For example, among Portuguese people carrying one of the most common TTR mutations, called Val30Met, about 89% develop hATTR-PN by age 60, compared with about 22% of Swedish carriers. By age 80, the rate among Portuguese carriers rises to 91%, while about two-thirds of Swedish carriers are estimated to develop the disease by age 90.
In contrast, a negative result means that you did not inherit the known family mutation and are not at risk of developing hATTR-PN or passing down the mutation to your children.
Why genetic counseling matters before testing
Genetic counseling can help you understand the benefits and limitations of testing before making a decision. A genetic counselor can explain what family testing for hATTR-PN can and cannot tell you, what different results may mean, and how the findings could affect your children, siblings, or other relatives.
Counselors may also help you navigate questions about timing, privacy, insurance concerns, and the emotional impact of learning your genetic risk.
Experts recommend genetic counseling both before and after testing, including support for discussing results with family members. Research also suggests that genetic counseling may reduce anxiety, improve understanding, and help people feel more confident in their decisions regarding their health.
Monitoring with no symptoms
If you test positive but do not have symptoms, follow-up care may start with an initial, or baseline, evaluation. This gives your healthcare team a starting point for tracking changes over time, helping them detect symptoms early. This is important because receiving treatment as soon as symptoms emerge is generally better for slowing disease progression and improving outcomes.
If you carry a TTR mutation, the best predictor of when your symptoms might appear is the age at which symptoms first appeared in affected family members. For this reason, experts generally recommend beginning monitoring about five to 10 years before the age of symptom onset in your affected relatives. However, monitoring may start sooner if the mutation is inherited from the mother’s side, or if symptoms develop.
Follow-up visits are often scheduled every 1-2 years and may focus on nerve health, heart health, and other possible complications linked to hATTR-PN. Monitoring may include:
- neurologic exams
- nerve testing
- blood pressure checks
- heart tests
- kidney tests
If symptoms do develop, early signs may include:
- pain, tingling, or numbness in the hands or feet
- dizziness or fainting when standing
- diarrhea, constipation, nausea, or feeling full quickly
- carpal tunnel syndrome
Questions to ask before deciding about testing
Before testing, it may help to think about what information you want and what support you may need. Consider asking your genetic counselor:
- What specific TTR mutation has been identified in my family?
- What can this test result tell me, and what can it not tell me?
- How could the results affect my children or siblings?
- What follow-up care would I need if I test positive?
With the right information, support, and guidance, you can make a testing decision that aligns with your needs, concerns, and future plans.
Amyloidosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
