[1] Baylor Coll Med, Dept Mol & Human Genet, Houston, TX 77030 USA
[2] Univ Texas Hlth Sci Ctr Houston, Sch Publ Hlth, Houston, TX USA
[3] Hosp Sick Children, Div Genet, Toronto, ON M5G 1X8, Canada
[4] Univ Western Ontario, Dept Biochem, London, ON, Canada
[5] Univ Western Ontario, Dept Pediat, London, ON N6A 3K7, Canada
[6] Univ Munich, Dept Neurol, Friedrich Baur Inst, D-8000 Munich, Germany
[7] Univ Technol, Dept Pediat, Metab Dis Ctr, Munich, Germany
[8] CHU Lyon, Ctr Biol & Pathol Est, Serv Malad Hereditaires Metab, Bron, France