[1] STATE UNIV UTRECHT, PHYSIOL CHEM LAB, UTRECHT, NETHERLANDS
[2] ERASMUS UNIV, DEPT CELL BIOL & GENET, 3000 DR ROTTERDAM, NETHERLANDS
[3] STATE UNIV UTRECHT, DEPT PEDIAT, UTRECHT, NETHERLANDS
[4] JOHNS HOPKINS UNIV, SCH MED, DEPT PEDIAT, BALTIMORE, MD 21205 USA
[5] STATE UNIV UTRECHT HOSP, DEPT INTERNAL MED, UTRECHT, NETHERLANDS