FBN1 Gene and Marfan Syndrome: Mutations and Clinical Trials
The FBN1 gene sits on chromosome 15q21.1, and its full name is fibrillin 1. Orphanet links FBN1 to 11 rare conditions and lists variants in the gene as a cause of 9 of them. Trial Friend's Marfan Syndrome page lists FBN1 among the genes behind the condition. As of September 29, 2026, 1 recruiting or soon-opening trial on ClinicalTrials.gov names FBN1 as a gene.
Other symbols for FBN1 in gene databases: MASS, OCTD, SGS.
What the FBN1 gene does
FBN1 makes fibrillin-1, a protein that builds threadlike microfibrils in the spaces between cells. These form the scaffolding for elastic fibers that let skin, ligaments and blood vessels stretch, and they help control growth factors.
Summarized from the FBN1 page on MedlinePlus Genetics, U.S. National Library of Medicine, checked September 29, 2026.
FBN1 and Marfan Syndrome
These condition pages list FBN1 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.
At least 25% of cases are new (de novo) FBN1 variants.
FBN1 mutation clinical trials
These recruiting or soon-opening trials mention FBN1 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.
1 trial, checked September 29, 2026. The list refreshes from ClinicalTrials.gov every few hours.
All conditions linked to FBN1 gene mutations
Orphanet records how each gene relates to each condition. Orphanet links FBN1 to 11 rare conditions and lists variants in the gene as a cause of 9 of them.
- Causes it. Disease-causing variants in this gene are a direct cause of the condition.
- Being studied. Researchers suspect a role that isn't confirmed yet.
FBN1 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 FBN1.
FBN1 gene questions
What does the FBN1 gene do?
FBN1 makes fibrillin-1, a protein that builds threadlike microfibrils in the spaces between cells. These form the scaffolding for elastic fibers that let skin, ligaments and blood vessels stretch, and they help control growth factors. This summary follows MedlinePlus Genetics from the U.S. National Library of Medicine.
Are there clinical trials for people with FBN1 gene variants?
As of September 29, 2026, 1 recruiting or soon-opening trial on ClinicalTrials.gov names FBN1 as a gene. Each one is listed on this page with the words from the trial that mention the gene. ClinicalTrials.gov also lists 19 open trials for Marfan Syndrome, and Match Me on Trial Friend can check those against age, sex, location and treatment history.
What conditions are linked to the FBN1 gene?
Orphanet links FBN1 to 11 rare conditions and lists variants in the gene as a cause of 9 of them. They include Marfan syndrome type 1, Neonatal Marfan syndrome, Acromicric dysplasia, Familial thoracic aortic aneurysm and aortic dissection, Geleophysic dysplasia, Isolated ectopia lentis and 5 more. Orphanet is the European rare disease database run by INSERM in Paris.
How is Marfan Syndrome inherited?
The inheritance pattern is autosomal dominant. One disease-causing variant can be enough to cause the condition. At least 25% of cases are new (de novo) FBN1 variants.
What does an FBN1 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.
- FBN1 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.