1. ; A. Szent-Györgyi Medical Centre; University of Szeged; Hungary
2. PKU Laboratory; Budapest Children's Hospital; Budapest
3. Department of Pediatrics; Erzsébet Hospital, Laboratory; Hódmez Hungary
4. ; General Clinical Research Center, Core Laboratory; University of Connecticut School of Medicine; Farmington Connecticut
5. Department of Pediatrics; Connecticut Children's Medical Center and the University of Connecticut School of Medicine; Hartford Connecticut USA