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TTR gene

Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

TTR gene

The TTR gene provides instructions for making the protein transthyretin, which transports vitamin A and thyroxine throughout the body.

Normal Function

The TTR gene provides instructions for making a protein called transthyretin. This protein transports vitamin A (retinol) and a hormone called thyroxine throughout the body. To transport thyroxine, four transthyretin proteins must attach to each other to form a unit called a tetramer. To transport retinol, transthyretin must form a tetramer and bind to another protein called retinol-binding protein. Transthyretin is produced primarily in the liver, with small amounts produced in the brain (choroid plexus) and the retina of the eye.

Health Conditions Related to Genetic Changes

Transthyretin amyloidosis

Variants in the TTR gene cause transthyretin amyloidosis. These variants alter the structure of transthyretin, impairing its ability to form tetramers. The tetramers break down into individual proteins that attach to each other to form strands called fibrils. These fibrils clump together to form amyloid deposits in certain tissues, leading to the condition's symptoms.

  • Val50Met (V50M): The most common variant, seen frequently in Portuguese and Swedish populations.
  • Val142Ile (V142I): A variant estimated to be present in 3 to 3.9 percent of African Americans and 5 percent of some West African populations.

Senile systemic amyloidosis

In some older adults, deposits of normal transthyretin proteins cause senile systemic amyloidosis. These individuals do not have a TTR gene variant. The condition most commonly affects the heart, causing progressive heart failure, but may also affect the lungs, blood vessels, and kidneys. It is estimated that 10 to 25 percent of people older than 80 have this condition.

Other Names for This Gene

  • ATTR
  • PALB
  • prealbumin, amyloidosis type I
  • TBPA
  • TTHY_HUMAN

Frequently Asked Questions

Val142Ile is most often associated with late‑onset cardiac amyloid, usually appearing in the 60s‑70s. The heart is the primary organ (congestive heart failure, arrhythmias, conduction disease), but some carriers also develop mild peripheral neuropathy or kidney involvement.
Watch for unexplained peripheral neuropathy (tingling, numbness), carpal tunnel‑like symptoms, unexplained heart failure with preserved ejection fraction, orthostatic dizziness, or unexplained gastrointestinal motility problems. New onset arrhythmias or thickened heart walls on echo in a relative‑age adult should trigger evaluation.
Yes. Maintaining a low‑salt diet, regular low‑impact aerobic exercise, and optimal blood pressure control can reduce cardiac strain. Avoiding excess alcohol and smoking helps. Some clinicians start tafamidis or diflunisal (off‑label) early, but definitive therapy (e.g., patisiran, inotersen, or liver transplantation) should be coordinated with an amyloidosis center.
You can request genetic testing through a clinical genetics lab or a specialist amyloidosis center. The test looks for known pathogenic variants (e.g., Val50Met, Val142Ile) using blood or saliva DNA. A pre‑test genetic counseling session is recommended to discuss implications for you and family members.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.