The results of four such studies that examined the genetic-environment association were presented at the annual meeting of the American Psychosomatic Society. The National Institute on Aging and the National Heart Lung and Blood Institute funded the studies.
The researchers examined the effect of mutation of a gene that produces monoamine oxidase-A. The enzyme is responsible for breakdown of serotonin and other neurotransmitters. Mutation of this gene can lead to either enhanced or decreased production of the chemical.
Neurotransmitters, as the name suggests are substances that communicate information to the brain. Therefore any change in level of these chemical substances can have a profound impact on brain function and other physiological functions, mediated by the brain such as glucose metabolism.
The mutation of the MAOA-uVNTR gene was found to determine the serotonin levels that had an indirect effect on blood levels of insulin, glucose and body mass index. This means that people who have a specific version of the gene could have an increased risk for development of diabetes and obesity.
Another study that examined the MAOA gene mutation in two different group of individuals; primary caregivers for spouses or relatives with Alzheimer's disease and those who were similar to caregivers, but had no responsibility of care giving. It was found that the levels of stress hormones, more specifically in men were to a large extent dependent on the type of MAOA gene mutation. Men with less active MAOA gene were at increased risk of developing health problems owing to their inability to cope up with the stress related to care giving.
The result of a study that evaluated the effect of a family of genes, known to influence stress response and high blood pressure (hypertension) was also presented at the symposium. The researchers hypothesize that genes which remain dormant when life is still and calm can become active under stress.
The importance of using genetic markers to identify at risk individuals for development of stress (those under acute/chronic stress, in addition to environmental factors such as high-calorie diet) was further highlighted. This could eventually pave way for effective treatment strategies or can assist in closely monitoring onset of diabetes or obesity.