19 exons.

2.8 Kb mRNA, 2049 bp open reading frame.

TGFBI is a 683 amino acid extracellular matrix protein, 68 kDa. Contains an N-terminal secretory signal peptide, a cysteine-rich domain, four internal homologous repeats (fasciclin-like FAS domains), and a C-terminal RGD motif.

TGFBI is normally found in thymus, bone marrow, spleen, brain, heart, skeleton muscle, lung, kidney, liver, pancreas, and prostate.

TGFBI is an extracellular matrix protein. It localizes in the extracellular matrix.

Binds to type I, II, IV, VI collagens and fibronectin. The RGD motif may serve as a ligand recognition sequence for integrins. The protein may be involved in cell-matrix interactions, cell adhesion, migration and differentiation. The protein may be involved in endochondrial bone formation in cartilage. The roles of TGFBI in malignant progression are controversial. Some studies suggested that TGFBI suppresses the progression of ovarian, lung cancer and neuroblastomas, while other reports identify TGFBI as an overexpressed gene in colon, pancreatic, and liver cancer.

TGFBI contains four FAS1 domains. Proteins cantaining the FAS domain include Arabidopsis fasciclin-like arabinogalactan proteins, bacterial immunogenic protein MPT70, human extracellular matrix protein periostin, and mammalian stabilin proteins.

Mutations in the human TGFBI gene have been linked to several inherited autosmal dominant corneal dystrophies. The abnormal protein deposits in the forms of amyloid fibrils and/or non-amyloid amorphous affregations in the corneal matrix. Progressive corneal cloudiness eventually leads to severe visual loss in later stage disease. Based on the clinial histopathological properties of the deposits, corneal dystrophy can be divided into two main types: lattice corneal dystrophy (LCD) and granular corneal dystrophy (GCD). These two types of corneal dystrophies are further divided into subtypes according to the differences in the clinical features of the disease. So far, 33 mutations have been identified in the TGFBI gene associated with all the GCDs and most of the LCDs, with two major mutational sites Arg124 and Arg555, accounting for more than half of all the patients with the disease.