Genetic Association of Recovery from Eating Disorders: The role of the GABA Receptor SNPs
Bloss CS, Berrettini W, Bergen AW, Magistretti P, Duvvuri V, Strober M, et al. Neuropsycholpharmacology. 2011 Jul; ahead of print
Eating disorders (ED) include anorexia nervosa, bulimia nervosa, and other patterns of disordered eatings that in many cases overlap among the different EDs. Most of the time, the onset of all EDs follow a specific pattern, which usually begins in early adulthood or adolescence and continues for 5 to 10 years. Then, the ED enters remission and the individual’s weight will become stabilized in their early 20’s. However, about 25% of patients with ED show no signs of remission or improvement. Genetic variations could be one factor that contributes to increasing risk or protecting a patient from a lifetime of ED. Identifying gene variants associated with ED remission or a lack thereof could lead to more personalized treatment protocols (e.g., psychotherapies, or pharmacological interventions). The purpose of this study was to evaluate single nucleotide polymorphisms (SNPs, common genetic variants) among 1,878 female participants (1201 cases with a history of ED and 677 controls) to determine if these genetic variants can identify patients likely to experience ED remission or not. The women were divided into 3 sets: 1) a set to initially identify genetic variants that are different between women over 25 years of age in ED remission (n = 115) or not in remission (n = 361), 2) a set to verify the initial findings among women under 25 years of age with and without symptoms during the year before testing (n = 107, 464; respectively), and 3) a set of 677 controls and 154 patients whose recovery status was unknown. Researchers focused on 5,151 genetic variants in approximately 350 genes. In the initial set of patients, a genetic variant in a region of GABRG1 (a gene in chromosome 4) was the most significant SNP with an association to ED recovery/remission. This was further verified in the second set of patients. In the third set (as well as among all 1,878 participants), the genetic variant was associated with lower levels of anxiety-related traits. The authors suggest that this last finding might help explain why this variant is associated with being more likely to experience remission than not to experience remission.
Research like this study may be a great benefit to sports medicine because these genetic studies may provide tools to identify individuals at risk for a condition, lead to discoveries of new treatments, and help lead to new ways of individualizing patient care. Genetic studies are important because genes provide the blue print to not only how we look, but also how we react to environmental factors. Variations within genes could lead to understanding why some people are more susceptible to diseases/injuries, or how they react differently to diseases/injuries (e.g., prolong recovery versus rapid healing/recovery). Research in this area could lead to a better understanding of risk factors for injuries and the physiology of the disease/injury/healing. This new knowledge could help improve injury prevention programs and lead to improved treatments. For example, there are already genetic studies being done to understand why some people can withstand a concussion and be fine the next day, while others sustain a similar head impact but are out for the season. While this study had a large sample size, the sample size in each distinctive cohort was small. Furthermore the study was based on retrospective data, which insinuates that there may be recall bias. It will be interesting to see larger prospective studies and other SNPs evaluating this research question to help eliminate some of these issues. In the coming years, genetics research will continue to grow in sports medicine and these studies will likely capture media attention. Therefore, we need to be prepared to have conversations about this area of research with our patients.
Written by: Jane McDevitt MS, ATC, CSCS
Reviewed by: Jeffrey Driban