Researchers at the University of Wisconsin-Madison have discovered that a protein known as Transmembrane 135 (Tmem135) is responsible for retinal aging. Mutations of Tmem135 causes age-related retinal disease including age-related macular degeneration. Using lab mice that matched similar retinal abnormalities that are found in mice that have early onset of retinal disease, the researchers mapped the genes of the lab mice and found the mutation in Tmem135, which they believed to be the cause of retinal conditions. Researchers also found that the protein was responsible for determining the pace of the retinal aging process. Researchers are now conducting further studies to figure out the exact biochemical function of Tmem135 in cell mitochondria as well as the role that it plays in changing the aging process in different tissues and other age-related diseases.