TTR Gene and ATTR Amyloidosis: Mutations and Clinical Trials
The TTR gene sits on chromosome 18q12.1, and its full name is transthyretin. Orphanet links TTR to 3 rare conditions and lists variants in the gene as a cause of all of them. Trial Friend's ATTR Amyloidosis (Transthyretin Amyloidosis) page lists TTR among the genes behind the condition. As of September 29, 2026, 10 recruiting or soon-opening trials on ClinicalTrials.gov name TTR as a gene.
Other symbols for TTR in gene databases: CTS, HsT2651.
What the TTR gene does
TTR makes transthyretin, a protein made mainly in the liver that carries vitamin A and the thyroid hormone thyroxine through the blood. To do this, 4 transthyretin proteins join into a unit called a tetramer.
Summarized from the TTR page on MedlinePlus Genetics, U.S. National Library of Medicine, checked September 29, 2026.
TTR and ATTR Amyloidosis (Transthyretin Amyloidosis)
These condition pages list TTR among the genes behind the condition, checked against genetics references when each page was written.
One disease-causing variant can be enough to cause the condition, though not everyone who carries it develops symptoms.
Hereditary ATTR is a TTR variant (V122I is common in people of African ancestry); wild-type ATTR, with no TTR variant, is an acquired form seen mainly in older men.
TTR mutation clinical trials
These recruiting or soon-opening trials mention TTR as a gene in their title, summary, eligibility rules or keywords. Some want people with a variant in it, and others study it more broadly, which is why each trial's own words are shown. In cancer trials the gene change is usually one found in the tumor rather than one a person inherited.
10 trials, checked September 29, 2026. The list refreshes from ClinicalTrials.gov every few hours.
All conditions linked to TTR gene mutations
Orphanet records how each gene relates to each condition. Orphanet links TTR to 3 rare conditions and lists variants in the gene as a cause of all of them.
- Causes it. Disease-causing variants in this gene are a direct cause of the condition.
TTR genetic test results and what a variant can mean
Labs sort each variant they find into 5 groups, from pathogenic and likely pathogenic through uncertain significance to likely benign and benign. Only the first 2 are usually treated as the cause of a condition. A variant of uncertain significance, or VUS, is one without enough evidence either way yet, and labs can reclassify it as research builds.
A genetic counselor or your doctor can explain what a specific result means for you and your family. Our genetic testing guide covers the terms, and MedlinePlus Genetics from the National Library of Medicine has a plain-language page on TTR.
TTR gene questions
What does the TTR gene do?
TTR makes transthyretin, a protein made mainly in the liver that carries vitamin A and the thyroid hormone thyroxine through the blood. To do this, 4 transthyretin proteins join into a unit called a tetramer. This summary follows MedlinePlus Genetics from the U.S. National Library of Medicine.
Are there clinical trials for people with TTR gene variants?
As of September 29, 2026, 10 recruiting or soon-opening trials on ClinicalTrials.gov name TTR as a gene. Each one is listed on this page with the words from the trial that mention the gene. ClinicalTrials.gov also lists 71 open trials for ATTR Amyloidosis (Transthyretin Amyloidosis), and Match Me on Trial Friend can check those against age, sex, location and treatment history.
What conditions are linked to the TTR gene?
Orphanet links TTR to 3 rare conditions and lists variants in the gene as a cause of all of them. They include ATTRV122I amyloidosis, ATTRV30M amyloidosis and Euthyroid dysprealbuminemic hyperthyroxinemia. Orphanet is the European rare disease database run by INSERM in Paris.
How is ATTR Amyloidosis (Transthyretin Amyloidosis) inherited?
The inheritance pattern is autosomal dominant with reduced penetrance. One disease-causing variant can be enough to cause the condition, though not everyone who carries it develops symptoms. Hereditary ATTR is a TTR variant (V122I is common in people of African ancestry); wild-type ATTR, with no TTR variant, is an acquired form seen mainly in older men.
What does a TTR variant of uncertain significance mean?
A variant of uncertain significance, or VUS, is a change in the gene that labs don't yet have enough evidence to call disease-causing or harmless. It is not used on its own to diagnose a condition, and labs can reclassify it as research builds. A genetic counselor can explain what a specific result means for you and your family.
Sources
- Gene and condition links from Orphadata (Orphanet, INSERM US14), used under CC BY 4.0, read September 29, 2026.
- Trials from ClinicalTrials.gov, read September 29, 2026.
- TTR gene, MedlinePlus Genetics, U.S. National Library of Medicine.
- Inheritance and gene notes from the Trial Friend condition pages above, each checked against genetics references.
Other gene pages
The gene search covers every gene Orphanet links to a rare disease.