[1] Duke Univ, Med Scientist Training Program, Durham, NC USA
[2] Duke Univ, Dept Pediat, Childrens Hlth & Discovery Inst, Durham, NC 27706 USA
[3] Duke Univ, Div Neuroepidemiol, Dept Neurosurg, Durham, NC USA
[4] Duke Univ, Dept Pediat, Div Med Genet, Durham, NC 27706 USA
[5] Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA USA
[6] Duke Univ, Sch Med, Dept Populat Hlth Sci, Durham, NC USA
[7] Duke Univ, Med Ctr, Duke Canc Inst, Durham, NC USA