Association of <i>ANKK1</i> and <i>DRD2</i> gene polymorphisms with exercise addiction among elite athletes

Exercise addiction is a behavior that may dysregulate athletic performance, and social and professional interactions of athletes. Whereas environmental factors including training routines and personal traits could contribute to exercise addiction, recent studies have emphasized the importance of genetic predisposition, leading to development of a subfield known as sports psychogenetics. In sports psychogenetics, ankyrin repeat and kinase domain containing 1 (ANKK1) and dopamine receptor D2 (DRD2) genes, located on chromosome 11 in a close proximity, have attracted research interest due to their involvement in dopaminergic signaling playing a crucial role in reward processing, motivation, cognition and behavior. Therefore, the present study aimed to investigate potential associations between 14 polymorphisms in ANKK1/DRD2 and exercise addiction among elite badminton players (n = 39) and elite wrestlers (n = 68). Exercise addiction was assessed using a psychometric screening instrument and allele frequencies of the selected polymorphisms were analyzed through genotyping with a single nucleotide polymorphism (SNP) microarray. Results indicated that two SNPs, rs7118900 and rs4436578, were significantly and independently associated with exercise addiction. Rs7118900 has previously been associated with an increased risk of drug addiction, neuroticism, and depressed effect whereas rs4436578 has been associated with neuroticism. In addition to those SNPS, rs2283265 and rs1125394 SNPs were also linked to exercise addiction in a branch-independent manner. Therefore, it is proposed that these SNPs could serve as genetic markers for identifying individuals at high risk of exercise addiction among athletes. However, further research is needed to understand the involvement of these SNPs in exercise addiction more comprehensively.