Article: http://www.healthandage.com/Home/gm=0!gc=15!l=1!gid1=1120;jsessionid=PlZ8bqI 9YMlHmBKdpXw7R79EgjckesRUoS9GtajdwBZGGdr6Yr1A!1495537831!174479252!7537!7002 Index to all articles: http://www.healthandage.com/Home/gm=0!gc=15!l=1 Ancient mutation controls lactose intolerance Researchers in Finland and the US believe they have located the genetic basis for lactose intolerance. Up to 50 million Americans, including 75 per cent of African Americans and 90 per cent of Asian Americans suffer from lactose intolerance. This is a painful digestive condition marked by nausea, cramping, bloating and diarrhoea when the affected person is exposed the lactose, the natural sugar in dairy products. No mutation has ever been found in the gene responsible for lactose breakdown to account for this condition. But when researchers in Los Angeles and Finland looked at a region close to, but outside , the gene they found a mutation in a group of 196 lactose intolerant people living in Finland. They found it in people of African, Asian and European descent. The fact it's so widespread across ethnic groups suggests this is an ancient mutation, with its roots far back in human history. The researchers wonder whether we were all lactose intolerant at one time, but the emergence of agriculture favoured the emergence of tolerance. The study opens up the way to more accurate diagnosis of lactose intolerance, based upon DNA analysis. Current diagnostic methods are uncertain and hard to carry out, so a new approach would certainly benefit those who need to know what is causing their symptoms. Source Nature Genetics January 14 2002