In the comparison of basal concentrations, the pooled SMDs were observed to be lower in obesity for basal active and total ghrelin, total GLP‐1, active PYY, and total PYY, although this was only statistically significant for basal total ghrelin (SMD: −1.42, 95% CI −2.07 to −0.76, I2 = 96.96%, p < 0.001) (Figure 2B). The gene discussed is PYY; the disease is obesity due to melanocortin 4 receptor deficiency.