RXRA and hyperinsulinemic hypoglycemia, familial, 4: We found that mechanical loading was associated with lower levels of DNA methylation at the RXRA B CpG 6 site in the non-loaded limb compared to the loaded limb in those exposed to early life deficiency (p = 0.026, mean difference = −4.7%, 95% CI: −8.80, −0.69; n = 6/group) (Fig. 1b).