SMPD1 and Niemann-Pick disease: For instance, clinical pilot study has shown that inhibition of ASM or ASM deficiency does not protect from GVHD in transplant recipients with Niemann–Pick disease.67 Meanwhile, considering the broad signals mediated by ASM/ceramide in response to diverse stimuli, inhibition of ASM may impact a variety of cell functions, some indispensable for maintenance of physical conditions of human body.