ACTN3 is associated with children's physical fitness in Han Chinese.

The ACTN3 gene locates on 11q13-q14 and encodes the α-actinin-3 protein, which is only expressed in human skeletal muscle and influenced muscle function and metabolism. The previous studies reported that SNP rs1815739 is associated with elite power athletes' performance. In this study, we investigated the association between five SNPs within the ACTN3 gene and Chinese children physical fitness. We recruited 2244 Han Chinese children participants, and measured their 25-m run, stand broad jump, 10-m shuttle run, handgrip, BMI (calculated by weight and height) data. SNPs rs1671064, rs2275998, rs2290463, rs10791881, and rs1815739 of ACTN3 gene were genotyped and analyzed in five physical fitness data. QTL analysis on genotype and physical fitness data was carried out in all samples. Furthermore, a dichotomous division of samples into an overweight group (543) and a normal group (1701) was used for an association study of overweight. In the QTL analysis, we found rs2290463 was significantly associated with stand broad jump (corrected P value = 0.009, beta = 2.692). After added age and gender as covariates in the regression test, the association became more significant (P value = 5.80 × 10- 5 , corrected P value = 4.06 × 10- 4 ); when we used BMI as a covariate, the association still existed (P value = 4.65 × 10- 4 , corrected P value = 0.001). In the association study of overweight, rs2275998 was found to be significant (OR, 95% CI = 0.733 [0.6-0.895]; Pallele  = 0.011, Pgenotype  = 0.024) after the Bonferroni correction, and the association did not change much after a further correction for gender, age, and stand broad jump performance. Our results showed that common variants in ACTN3 are significantly associated with both stand broad jump performance and overweight in Han Chinese children.