While we show the powerfulness of trappc9-deficient mice in investigating obesity development and uncover several cellular pathways that are perturbed by the deficiency of trappc9 in mice, our study is limited in exploring the molecular underpinnings behind the perturbation of these pathways and lacks attempts to examine whether the perturbation can be attenuated upon restoring trappc9. This evidence concerns the gene TRAPPC9 and obesity due to melanocortin 4 receptor deficiency.