[1] Univ Calif Los Angeles, Dept Human Genet, Los Angeles, CA 90024 USA
[2] Univ London Imperial Coll Sci & Technol, MRC, Ctr Clin Sci, London, England
[3] Univ Helsinki, Dept Med, Helsinki, Finland
[4] Acad Hosp Maastricht, Dept Med, CARIM, Maastricht, Netherlands