Deletion of SLC6A14 in mice does not lead to significant detrimental consequences under normal conditions (Babu et al., 2015), even though the null mice are resistant to certain cancers (Babu et al., 2015; Schniers et al., 2022) and also are prone to obesity when fed a high-fat diet (Sivaprakasam et al., 2021b). The gene discussed is SLC6A14; the disease is obesity due to melanocortin 4 receptor deficiency.