Latent trait and epigenetic analysis of ACTN3 gene polymorphism Homo-RR in Japanese college students

BACKGROUND: Alpha-actinin-3, encoded by the ACTN3 gene, is presumably associated with sprint/power ability. However, the difference in athletic performance between the RR and deficient types (XX) is unremarkable in the general population. Thus, it is necessary to further elucidate the involvement of epigenetic mechanisms, such as DNA methylation, to evaluate a participant’s exercise performance. Hence, this study aimed to identify DNA methylation in the upstream sense strand region of ACTN3 among the RR genotype-manifesting male college students.METHODS: The study included 25 male students aged 18-20 years who were homozygous for the R577X polymorphism of ACTN3. DNA was extracted from hair as the sample and methylation analysis was performed using the bisulfite treatment method.RESULTS: Methylation analysis of 480 bases in the analyzed promoter region revealed methylation of cytosine bases in samples from nine participants (36% of the total participants), including five samples with methylation in CpG and four in non-CpG. Since methylation was observed in approximately 40% of the participants, it is expected that methylation occurs in the region around 480 bases of the sense strand, as well as in other regions such as the antisense strand, the gene region, and the terminator region, suggesting that RR-type methylation may be prominent.CONCLUSIONS: Thus, the sprint/power ability, characterized by ACTN3, may not be pronounced in the general population. This study suggested that epigenetics-based analysis methods are important than genotype-based analysis methods.