[1] Yale Univ, Sch Med, Sect Digest Dis, Sect Pediat Gastroenterol & Hepatol,Dept Pediat, New Haven, CT 06520 USA
[2] Yale Univ, Sch Med, Dept Pediat, Sect Pediat Hematol Oncol, New Haven, CT 06520 USA
[3] Yale Univ, Sch Med, Dept Genet, Howard Hughes Med Inst, New Haven, CT 06520 USA
[4] Yale Univ, Sch Med, Dept Pathol, New Haven, CT 06520 USA
[5] Univ Amsterdam, Acad Med Ctr, Dept Biochem, NL-1105 AZ Amsterdam, Netherlands
[6] Yale Univ, Sch Med, Sect Digest Dis, Dept Internal Med, New Haven, CT 06520 USA