affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, C.O.A.L.A (Center for diagnosis and treatment of 5eukodystrophies), affiliation not provided to SSRN, affiliation not provided to SSRN, Children’s Hospital of Philadelphia, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, McGill University, National Center of Neurology and Psychiatry, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, McGill University, National Center of Neurology and Psychiatry, affiliation not provided to SSRN, affiliation not provided to SSRN, University of Pennsylvania and University of Pennsylvania