[1] GKT, Sch Med, Div Med & Mol Genet, London, England
[2] Western Gen Hosp, SE Scotland Reg Genet Serv, Edinburgh EH4 2XU, Midlothian, Scotland
[3] Duke Univ, Sch Med, Dept Genet, Durham, NC 27706 USA
[4] Inst Mol Biol Zelikulturtech, Mannheim, Germany
[5] Vermont Reg Genet Ctr, Burlington, VT USA
[6] NHGRI, Bethesda, MD 20892 USA