To include variations contributed by the purity of different BrMV isolates and by the physiological condition of the brain, we isolated 10 pairs of brain samples (BrMV and CDB), including 4 samples from normal C57/Bl6 mice (WT), 4 samples from mice with a neurological lysosomal storage disease (Hurler syndrome, Idua-deficient)[34] and 2 samples from heterozygotes for Idua (Het). The gene discussed is IDUA; the disease is Hurler syndrome.