Biosynthesis and turnover of 1-deoxy-sphingoid bases (1-doexySLs). 1-Deoxysphingolipids differ structurally from canonical SLs as they lack the essential C1-OH group. Consequently, 1-deoxysphingolipids cannot be converted to complex sphingolipids and are not degraded over the canonical catabolic pathways. Further conversion of 1-deoxysphingosine is done by members of the CYP4A/F family. It is however not clear which specific genes are involved in these processes.