[1] NHGRI, Social & Behav Res Branch, NIH, Bethesda, MD 20892 USA
[2] Johns Hopkins Sch Publ Hlth, Dept Hlth Behav & Soc, Baltimore, MD USA
[3] Johns Hopkins Univ, McKusick Nathans Inst Genet Med, Baltimore, MD USA
[4] RTI Int, Res Triangle Pk, NC USA
[5] Sanford Hlth, Genet Counseling Dept, Sioux Falls, SD 57117 USA
[6] RTI Int, Washington, DC USA