[1] Univ Manchester, MAHSC, St Marys Hosp, Manchester M13 9WL, Lancs, England
[2] Vrije Univ Amsterdam, Metab Unit, Dept Clin Chem, Inst Cardiovasc Res,Med Ctr Amsterdam, NL-1081 HV Amsterdam, Netherlands
[3] Cent Manchester Univ Hosp NHS Fdn Trust, MAHSC, St Marys Hosp, Manchester M13 9WL, Lancs, England
[4] Univ Montreal, Dept Biochim, Montreal, PQ H3C 3J7, Canada
[5] Univ Montreal, Dept Chim, Montreal, PQ H3C 3J7, Canada
[6] Radboud Univ Nijmegen, Dept Human Genet, Inst Genet & Metab Dis, Med Ctr, NL-6525 GA Nijmegen, Netherlands
[7] Cent Manchester Fdn NHS Trust, MAHSC, St Marys Hosp, Manchester M13 9WL, Lancs, England
[8] Vrije Univ Amsterdam, Dept Internal Med, Inst Cardiovasc Res, Med Ctr Amsterdam, NL-1081 HV Amsterdam, Netherlands
[9] Radboud Univ Nijmegen, Lab Genet Endocrine & Metab Dis, Dept Lab Med, Med Ctr, NL-6525 GA Nijmegen, Netherlands
[10] Univ Gottingen, Dept Pediat, D-37075 Gottingen, Germany
[11] Great Ormond St Hosp Sick Children, Neurometab Unit, Natl Hosp, Clin & Mol Genet Unit,UCL Inst Child Hlth & Enzym, London WC1N 3JH, England
[12] Great Ormond St Hosp Sick Children, Metab Unit, London WC1N 3JH, England