[1] Univ Tampere, Inst Med Technol, SF-33101 Tampere, Finland
[2] Univ Tampere, Univ Hosp, SF-33101 Tampere, Finland
[3] Keio Univ, Sch Med, Dept Mol Biol, Shinjuku Ku, Tokyo 160, Japan
[4] Univ Geneva, Sch Med, Dept Genet & Microbiol, Lab Human Mol Genet, Geneva 4, Switzerland