Macular degeneration is one of the leading causes of blindness in people over the age of 60 and a trans-Atlantic study may have found the culprit behind this problem. Researchers from the University of Southampton in the UK and the University of Iowa in the US believe the Serping 1 gene is responsible for age-related macular degeneration (AMD). This discovery is expected to help scientists find better treatments and improve screening processes for patients. The finding was recently published online in the journal Lancet. AMD affects the area at the back of the eye, which is the part of the eye that allows people to see objects in fine detail. The researchers postulate that 33% of the population over the age of 75 will eventually suffer from AMD. Past data have indicated that almost 66% of octogenarians suffer from AMD and over 10% are left blind by the disease. The researchers found the Serping 1 gene in 25% of their study participants. In the past, researchers identified other genes or genetic loci (particular locations on chromosomes that contain functional genes) impacting how susceptible a person is to AMD. The new research showed that a variant of the Serping 1 gene helps trigger the production of proteins for 'the complement system' within the eye, in particular the retina and choroid layer - the two areas affected by AMD. The proteins help regulate a part of the body's innate immune system, what experts call the 'complement system'. The research revealed that the Serping 1 gene makes the complement system overwork, triggering a malfunction that causes the retina and choroid layer to come under attack. The effect is not quick, however. It could take some 70 years to develop, the researchers noted. University of Southampton's Professor Andrew Lotery, co-author of the study, remarked that although it 'seems counterintuitive that a generalised innate immunity defence system should result in a localised disease of the eye in the elderly', the research provides evidence that it is the case. The Southampton team said the annual economic burden from the disease could reach GBP 80 million (around EUR 100.4 million) in the UK alone. According to the researchers, this figure could rise as the number of older people grows. The research also showed that the costs of healthcare increased seven-fold for AMD sufferers versus non-AMD patients. Concerning how the current research will affect future work, Professor Lotery commented: 'It means that we can diagnose people at an earlier stage and we can have more focused treatments, perhaps just even drug therapies that we can provide before people develop the late stages of the disease.'