Studies indicate that NOD mice exhibit decreased S1P1 and sphingosine-1-phosphate lyase (SGPL1) expression in thymocytes, along with T-cell migration abnormalities, implying that regulation of S1P1 and its interactions in thymocytes may play a role in the onset of type 1 diabetes (34). This evidence concerns the gene SGPL1 and type 1 diabetes mellitus.