FBN3

FBN3 stands for fibrillin-3, a member of the fibrillin family of extracellular matrix glycoproteins. Fibrillins assemble into microfibrils that provide structural support to connective tissues and help regulate signaling for transforming growth factor-beta (TGF-β). FBN3 encodes a large secreted protein whose domain organization is consistent with other fibrillins, including multiple epidermal growth factor-like repeats and TB modules, suggesting a role in microfibril formation and matrix architecture.

In humans, expression of FBN3 has been reported in several tissues, with some data indicating presence in placenta, skeletal muscle, and brain. The available expression data are limited and not always consistent across studies, reflecting the need for more comprehensive profiling.

Functionally, fibrillin-3 is less well characterized than its paralogs fibrillin-1 and fibrillin-2. It is presumed to contribute to extracellular matrix networks and to influence TGF-β signaling indirectly through its incorporation into microfibrils, but specific roles in development, tissue mechanics, or physiology are not well defined. There is no consensus on distinct, essential functions attributable to FBN3 from human genetic studies to date.

Clinical significance remains uncertain. No robust, replicated links have established FBN3 mutations or variants as causes of a defined inherited connective tissue disorder. Some exploratory studies have examined potential associations with traits such as myopia or other phenotypes, but results have been inconclusive and require further validation.

Evolutionarily, FBN3 is part of the fibrillin gene family and has orthologs in other vertebrates, indicating conservation of some aspect of fibrillin function across species.