GENE REFERENCE / HGNC:3603

FBN1

fibrillin 1

protein-coding gene15q21.1Gene information

What does this gene do?

The FBN1 gene provides instructions for making a large protein called fibrillin-1. This protein is transported out of cells into the extracellular matrix, which is an intricate lattice of proteins and other molecules that forms in the spaces between cells. In the extracellular matrix, fibrillin-1 proteins bind to each other and to other proteins to form threadlike filaments called microfibrils, which are organized into a network. This microfibrillar network acts as a platform or scaffold for the assembly of elastic fibers, which enable the skin, ligaments, and blood vessels to stretch. The microfibrillar network also provides support to the bones and to the tissues that support the nerves, muscles, and lenses of the eyes.

As part of the microfibrillar network, fibrillin-1 also regulates certain growth factor proteins. Growth factors are important proteins that help regulate cell processes such as the growth and division (proliferation) of cells, the process by which cells mature to carry out specific functions (differentiation), cell movement, and the self-destruction of cells (apoptosis). A particular growth factor called transforming growth factor beta (TGF-β) is stored within the microfibrillar network. When it is stored, TGF-β is turned off. Once it is released from the network, TGF-β is turned on and can activate important signaling pathways, including those involved in bone formation. By helping to regulate the availability of TGF-β, fibrillin-1 also helps regulate its activity.

Source: MedlinePlus, National Library of Medicine. Source publication: 2026-04-01. Source review: 2026-04.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
familial thoracic aortic aneurysm and aortic dissectionMONDO:0019625 · Evaluated 2017-01-23	Autosomal dominant	DefinitiveHeritable Thoracic Aortic Aneurysm and Dissection Gene Curation Expert Panel
Shprintzen-Goldberg syndromeMONDO:0008426 · Evaluated 2021-12-01	Autosomal dominant	DisputedIntellectual Disability and Autism Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 9,717
Submissions for variants in or overlapping this gene: 21,467
Submissions explicitly reporting this gene: 21,169
Alleles reported pathogenic / likely pathogenic: 3,849
VariationIDs with uncertain significance: 2,827
VariationIDs with conflicting classifications: 733

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about FBN1?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 3,849 alleles in FBN1 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in FBN1.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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