The purpose of the study is to better understand how the body handles sugars glucose and fats, such as cholesterol and triglycerides in sickle cell disease, and what puts certain persons at risk to develop diabetes. This understanding may help us to find new treatments to control blood sugar and prevent diabetes in people with and without sickle cell disease (SCD). In this research, DNA and RNA will be isolated from blood cells. DNA will be used to find genes that cause or protect from diabetes, high cholesterol and high triglyceride, and RNA will be used for studies designed to find out how genes are doing their job of eventually producing proteins.