Transforming growth factor-beta-induced protein ig-h3 (BIGH3) binds to type I, II, and IV collagens. BIGH3 plays a role in cell-collagen interactions. In cartilage, BIGH3 is involved in endochondral bone formation. Defects in BIGH3 are the cause of epithelial basement membrane corneal dystrophy (EBMD), also known as Cogan corneal dystrophy or map-dot-fingerprint type corneal dystrophy. EBMD is a bilateral anterior corneal dystrophy characterized by grayish epithelial fingerprint lines, geographic map-like lines, and dots (or microcysts) on slit-lamp e, Xenopus/Amphibian,amination. Pathologic studies show abnormal, redundant basement membrane and intraepithelial lacunae filled with cellular debris. Although this disorder usually is not considered to be inherited, families with autosomal dominant inheritance have been identified.