[1] Univ Duisburg Essen, Univ Hosp Essen, Inst Human Genet, D-45122 Essen, Germany
[2] St Marys Hosp, Manchester Acad Hlth Sci Ctr, Manchester Ctr Genom Med, Manchester M13 0JH, Lancs, England
[3] Univ Florida, Coll Med, Dept Pediat, Div Genet & Metab, Gainesville, FL USA
[4] Med Univ Lubeck, Inst Humangenet, D-23538 Lubeck, Germany