HTR1A and obesity due to melanocortin 4 receptor deficiency: We found significant negative correlations between obesity maps and dopamine transporter, D2 receptor, vesicular acetylcholine transporter, and serotonin 1a receptor, and positive associations with GABAa receptor and serotonin 1b receptor in the UKBB sample (Fig. 1, Fig. S3, Supplementary Data 5).