SLC6A14 and obesity due to melanocortin 4 receptor deficiency: Mutations in SLC6A14 have been shown to be associated with obesity in three independent populations [35],[36] and multiple SLC6A14 SNPs are suggestively associated (nominal p-value∼10−4–10−5) with waist circumference and weight in type 2 diabetes patients studied in the Diabetes Genomics Initiative genome-wide association study [37],[38].