[1] Johns Hopkins Univ, Bloomberg Sch Publ Hlth, Dept Biochem & Mol Biol, Baltimore, MD 21205 USA
[2] Johns Hopkins Univ, Bloomberg Sch Publ Hlth, W Harry Feinstone Dept Mol Microbiol & Immunol, Baltimore, MD 21205 USA
[3] Johns Hopkins Univ, Sch Med, McKusick Nathans Dept Genet Med, Baltimore, MD 21205 USA
[4] Johns Hopkins Univ, Sch Med, Dept Oncol, Baltimore, MD 21205 USA
[5] Johns Hopkins Univ, Sch Med, Dept Mol Biol & Genet, Baltimore, MD 21205 USA