Clue to infant heart disease risk

An abnormal gene may explain why small babies are more likely to develop heart disease later in life, say scientists.

An abnormal gene may explain why small babies are more likely to develop heart disease later in life, say scientists. Researchers in Canada believe a flaw in the APOE gene causes the arteries to harden and narrow. They say a version of this gene, which normally stops this from happening, is not passed on to small babies. Previous studies have shown underweight babies have a greater chance of developing heart disease when they grow old. DNA testsDr Claire Infante-Rivard and colleagues at McGill University in Montreal carried out DNA tests on 440 babies and their mothers and 194 fathers. All of the babies were born after 24 weeks of pregnancy but were below their expected weight at delivery. “We don’t know why this occurs” Dr Rebecca Reynolds,University of Edinburgh The researchers tested for the presence of the APOE gene. It comes in three versions – e2, e3 and e4. Together, they play a key role in maintaining the immune system, controlling cell growth and development in the brain. They also provide the genetic instructions for producing essential fat and protein in blood. Tests in animals have shown that when this gene is not working properly it increases the risks of arteries hardening and narrowing. This occurs because it is no longer able to stop the arteries from “furring up”. The researchers found the babies had normal levels of the e4 version of this gene and slightly higher levels of e3. However, they had much lower levels of the e2 version. This led the researchers to speculate this may explain why small babies are more likely to get heart disease later in life. But they added the findings need to be backed up by other scientists. Writing in the Journal of Medical Genetics, they said: “Despite the plausibility of our results, they need to be replicated in independent studies.” Hormonal changesDr Rebecca Reynolds, a clinical lecturer at the University of Edinburgh, is also carrying out research to find out why small babies are more likely to develop heart disease when they are older. It is a relatively new area of research not least because for years the medical community did not believe there was a link. “Until recently this was viewed as an hypothesis but it is becoming more and more accepted,” she told BBC News Online. She is looking at whether hormonal changes in the womb are to blame. “We are looking at stress hormones to see if changes in the womb permanently affect the physiology of these children, if they are predisposed to stress which can increase the risks of heart disease. She suggested much more research is needed. “Research in this area is wide open. Some people are looking at genes. We are looking at hormonal changes. “Others are looking at environmental factors. We don’t know why this occurs,” she said. (Source: BBC, 17 August 2003)