Further, other sphingolipid metabolic enzymes that function upstream of the hydrolysis of glucosylceramide (GCer) and sphingomyelin (SM) in the epidermis, such as serine-palmitoyl transferase (SPT), stearoyl CoA desaturase (SCD) [22], ceramide synthases (CERS) 1-5 [22], GCer synthase (GCERS), alkyl chain elongation enzymes [22] and SM synthase (SMS) have never been reported in uninflamed non-lesional AD skin to be implicated in the ceramide deficiency. The gene discussed is SCD; the disease is Alzheimer disease.