Three hundred eighty subjects diagnosed with AD (cases) and 253 healthy control subjects (screened to exclude major psychiatric illness) were recruited at three centers, including the University of Connecticut Health Center (Farmington) [224 cases (93 females (mean age 38.1 ± 11.3 yr) / 131 males (mean age 40.3 ± 11.29 yr) and 110 controls (77 females (mean age 39.9 ± 9.98 yr) / 33 males (mean age 38.9 ± 9.52 yr)], Yale University School of Medicine (New Haven, CT) [133 cases (52 females (mean age 38.6 ± 10.8 yr) / 81 males (mean age 38.0 ± 11.4 yr) and 52 controls (35 females (mean age 34.2 ± 10.2 yr) / 17 males (mean age 33.7 ± 11.4 yr)], and the Medical University of South Carolina (Charleston) [23 cases (6 females (mean age 39.2 ± 14.1 yr) / 17 males (mean age 35.0 ± 11.0 yr) and 91 controls (77 females (mean age 35.1 ± 11.4 yr) / 14 males (mean age 42.5 ± 12.3 yr)]. All subjects were of substantial African descent and all provided written informed consent as approved
