[1] UNIV IOWA,DEPT PEDIAT,IOWA CITY,IA 52242
[2] UNIV UTAH,HLTH SCI CTR,HOWARD HUGHES MED INST,SALT LAKE CITY,UT 84112
[3] NEW YORK STATE DEPT HLTH,ROSWELL PK MEM INST,DEPT HUMAN GENET,BUFFALO,NY 14263
[4] UNIV CHICAGO,DEPT BIOCHEM & MOLEC BIOL,CHICAGO,IL 60637
[5] UNIV CHICAGO,DEPT MED,CHICAGO,IL 60637