SMPD1 and obesity due to melanocortin 4 receptor deficiency: Interestingly, acid sphingomyelinase (ASMase)-mediated increases in ceramide were found to be associated with podocyte injury and glomerulosclerosis during hyperhomocysteinemia and obesity [10], indicating that not only ceramides synthesized via the de novo pathway are toxic to the cells but ceramides produced by the action of ceramidases or sphingomyelinases are equally toxic to cells.