[1] N Carolina Agr & Tech State Univ, Coll Arts & Sci, Dept Biol, Greensboro, NC 27411 USA
[2] Duke Univ, Med Ctr, Duke Pain & Palliat Care Ctr, Durham, NC USA
[3] Duke Univ, Med Ctr, Dept Psychiat, Durham, NC 27710 USA
[4] Duke Univ, Med Ctr, Duke Ctr Human Genet, Durham, NC USA
[5] Duke Univ, Med Ctr, Dept Med, Durham, NC 27710 USA
[6] Univ Miami, Miami Inst Human Genom, Coral Gables, FL 33124 USA