DIO3 and obesity due to melanocortin 4 receptor deficiency: Our study showed that obesity attenuated DNA methylation and accordingly enhanced the expression of DIO3. Although there is a lack of research on DIO3 gene methylation and expression in obesity, one research showed that DIO3 mRNA was increased in omental and subcutaneous white adipose tissues of obese men and women patients compared to their lean counterparts [28].