DEGS1 and Alzheimer disease: We also measured the expression of two other sphingolipid synthesis genes, i.e. lipid desaturase (DEGS1, converts dihydroceramide to ceramide) and UDP glycosyltransferase 8 (UGT8, converts ceramide to galactosylceramide) and found that neither were significantly altered in AD brain (Figure 1C,D).