The tissue inhibitors of metalloproteinases (TIMPs) play a crucial role in the physiological turnover of the extracellular matrix (ECM) by tightly regulating matrix metalloproteinase (MMP) activities. Disturbances in the TIMP/MMP system have been implicated in many disease processes where loss of ECM integrity is a principal feature. More recently, we have shown that mutations in TIMP3 cause the autosomal dominant disorder Sorsby's fundus dystrophy (SFD). This is a macular degeneration disorder with characteristic ECM irregularities in Bruch's membrane. To further facilitate mutational analysis and to provide a basis for functional studies, we now report the genomic organization of the human TIMP3 gene.