5.1.99.6	medicine	pathogenic biallelic mutations in NAXE in children from four families lead to (sub-)acute-onset ataxia, cerebellar edema, spinal myelopathy, and skin lesions. Lactate is elevated in cerebrospinal fluid of all affected individuals. Disease onset is during the second year of life and clinical signs as well as episodes of deterioration are triggered by febrile infections. Disease course is rapidly progressive, leading to coma, global brain atrophy, and finally to death in all affected individuals. NAXE levels are undetectable in fibroblasts from affected individuals of two families. These fibroblasts show highly elevated concentrations of the toxic metabolite cyclic-NADHX	746703