The present invention includes methods for treatment and prophylaxis of conditions associated with lactosylceramide. The methods generally provide for administration to a mammal, particularly a human, of a therapeutically effective amount of a compound that increases enzymatic activity of UDPGal:GlcCer.beta.1.fwdarw.4 galactosylceramide (GalT-2). In vitro and in vivo assays for detecting compounds with therapeutic capacity to modulate GalT-2 are also provided.