GBA1 and Parkinson disease: High levels of glucosylceramides have been associated with sporadic Parkinson’s disease [89,90,91] and neurologic forms of Gaucher disease [92,93,94] that result from heterozygous or homozygous “loss-of-function” mutations of the GlcCer-degrading enzyme, acidic lysosomal glucocerebrosidase (GBA1).