Emerging research suggests that a very small difference in a single gene affects the rate at which men’s intellectual function drops with advancing age

Investigators at the Stanford University School of Medicine and the Veterans Affairs Palo Alto Health Care System say that changes in the coding pattern of a particular gene appear to cause the variations. In the study, researchers tested the skills of experienced airplane pilots and found that having one version of the gene versus the other version doubled the rate at which the participants’ performance declined over time. The particular genetic variation, or polymorphism, implicated in the study has been linked in previous studies to several psychiatric disorders. However, this is the first acknowledgment that the genetic variation influences skilled task performance in the healthy, aging brain said the study’s senior author, Ahmad Salehi, M.D., Ph.D. The study also showed a significant age-related decline in the size of a key brain region called the hippocampus, which is crucial to memory and spatial reasoning, in pilots carrying this polymorphism. “This gene-associated difference may apply not only to pilots but also to the general public, for example in the ability to operate complex machinery,” said Salehi. The gene influences a protein called brain-derived neurotropic factor, or BDNF, which is critical to the development and maintenance of the central nervous system. As BDNF levels decline gradually with age even in healthy individuals; researchers have suspected that this decline may be linked with age-related losses of mental function. In the current study, researchers reviewed the effects of a small variation or polymorphism that occurs when one protein component is substituted for another. This alternative version has been linked to higher likelihood of depression, stroke, anorexia nervosa, anxiety-related disorders, suicidal behavior and schizophrenia.