Oligodendroglial inactivation of ceramide glucosyltransferase (UGCG), the limiting enzyme in the synthesis of all the gangliosides, resulted in minor changes in the myelin structure, whereas conditional knock-out mice in neurons, apparently normal at birth, showed progressive peripheral demyelination, ataxia, severe motor defects, and died within three weeks [36]. The gene discussed is UGCG; the disease is cerebellar ataxia.