In line with these findings, gene expression abnormalities of the key enzymes that control sphingolipid metabolism were found in AD patients: enzymes involved in glycosphingolipid synthesis (e.g., UDP-glucose ceramide glucosyltransferase) were altered accompanied by changes in enzymes resulting in the accumulation of Cer (e.g., serine palmitoyltransferase, neutral sphingomyelinase, and acid sphingomyelinase) [131, 133]. Here, SMPD2 is linked to Alzheimer disease.