[1] Stanford Univ, Sch Med, Dept Genet, Stanford, CA 94305 USA
[2] Stanford Genome Technol, Palo Alto, CA 94304 USA
[3] Univ Toronto, Dept Mol & Med Genet, Toronto, ON M5S 1A8, Canada
[4] New York State Dept Hlth, Wadsworth Ctr, Albany, NY 12201 USA
[5] Terrence Donnelly Ctr Cellular & Biomol Res, Toronto, ON M5S 3E1, Canada
[6] Banting & Best Dept Med Res, Toronto, ON M5S 1L6, Canada