The replication study samples included four cohorts of African-American subjects. The community nondiabetic replication cohort (cohort 3) includes 621 subjects (616 unrelated subjects and 5 related subjects from two nuclear families) who reported no history of diabetes were recruited from the community and internal medicine clinics similar to that of cohort 1. The diabetic replication cohort (cohort 4) consisted of 891 subjects with T2DM and 617 subjects with T2DM-ESRD (1,005 unrelated subjects and 503 related subjects from 178 nuclear families) recruited from the community, churches, health fairs, medical clinics, and dialysis facilities. The Diabetes Heart Studies cohort (cohort 5) consisted of subjects recruited from the community and internal medicine clinics in two studies that examine the subclinical cardiovascular risk in T2DM. A subset of 211 unrelated subjects from the African American-Diabetes Heart Study (27) and 81 subjects from the family based Diabetes Heart Study (28) were included in this study. All subjects from cohorts 1–5 were recruited in North Carolina, South Carolina, Georgia, Tennessee, or Virginia. The Insulin Resistance Atherosclerosis (IRAS) Studies cohort (cohort 6) consisted of subjects recruited from
