Glycolipid accumulation in the brains of 4-month-old Hexa −/−, Hexb −/−, and Gm2a −/− mice. (A) The sphingolipid fraction of brain tissues was separated by thin-layer chromatography. GM2 and GA2 standards are indicated. g, gray matter; w, white matter. (B) The sphingolipid fraction of gray and white matter was quantified, respectively (μmol/g wet weight).