DRD1 and obesity due to melanocortin 4 receptor deficiency: As the treatment combining DRD1 antagonist SCH23390 and DRD2 agonist quinpirole is effective in ameliorating deficits associated with multiple behaviors in Trappc9-KO mice (19), we reasoned that this treatment might also be beneficial in controlling obesity or NAFLD in Trappc9-KO mice.