Assessing Sequence Variations in the Leptin Gene in African Americans

摘要

Obesity has become the nation's number one health issue and is impacted by factors such as genetic predisposition, nutrition, and environment. Sixty-five percent of American adults are overweight or obese, and the rate has more than doubled (15%) in children ages 6-11. Leptin, an adipo-cyte-derived peptidic hormone and product of the obesity gene, has been linked to several diseases such as obesity, diabetes, heart disease, post-menopausal breast cancer, pituitary dysfunction, infertility, and bone density. Cloning of the ob (lep) gene has greatly advanced our understanding of the mechanisms involving obesity. Leptin is encoded by a gene located on human chromosome 7q31.3 and demonstrates structural similarities with the cytokine family. Research has shown that sequence variants in the 5' flanking region of lep gene were found to be associated with obesity. Rare forms of human obesity have now been identified where mutations in leptin receptors might play a major role in the development of the disease. These previous studies involving obesity included few African American participants. Therefore, the present study under Project EXPORT focuses on the molecular aspect of obesity in African Americans as a health disparity of major concern. The research correlates serum parameters with SNP's in the leptin gene. The 120 subjects were categorized based on age and weight with 17% normal, 27% overweight, and 56% obese. PCR tests were used to screen 120 participants' DNA with primers specific to the Lep gene. For the Lep gene, the expected 242 bp fragment was digested with Cfo I to yield three bands (242, 181, and 61 bp) indicating a single nucleotide (G to A) polymorphism at locus 2548 in the promoter of the Lep gene. The pathogenicity of obese people in this study follows the same pattern as the national obesity prevalence in minority communities. Tuskegee University Project EXPORT/NIH-NCMHD.