Absence of mutations in the human OB gene in obese/diabetic subjects.

The product of the obese (ob) gene, leptin, is a secreted protein that is important in the regulation of body weight. Mice with mutations in the ob gene are obese and diabetic and manifest reduced physical as well as metabolic activity. In this study, we tested the possibility that mutations in the OB gene may contribute to human obesity. We report the isolation and partial sequence of the human OB gene and the screening of 105 obese patients for mutations in the protein coding sequence using the technique of single-strand conformational polymorphism. No coding sequence polymorphism was found, suggesting that mutations in the coding sequence of the OB gene do not constitute a common cause of increased body weight in humans. We also identified a highly polymorphic simple dinucleotide repeat DNA polymorphism in this gene that will be useful for genetic studies.