Human subjects

The details of human subjects and recruitment criteria for families have been described previously [19]. Briefly, 82 (60 Caucasian and 22 African American) families with 2 parents and 2 biological children were recruited from the general population, residing in the greater Sacramento area using community reach approaches (e.g., meetings with local community members and leaders, informational presentations at community gatherings, distributions of flyers). Families were invited to the University of California (UC) Davis Clinical and Translational Science Center for collection of demographic and medical history information using standardized questionnaires, physical examinations and for blood draws. Race/ethnicity was self-reported for each individual family member, and 182 individuals self-identified as Caucasians and 87 individuals as African Americans. Data from 2 children (1 in each ethnic group) were not included due to unavailability of blood samples, and the present report is based on findings in 181 Caucasians and 86 African Americans. The study was approved by the UC Davis Institutional Review Board and informed consent obtained from all subjects. Minors were asked to give their assents (assent form for 12-17 years old; or letter of information for 8-11 years old), and one of the parents signed the consent forms for their children.