The present invention provides a neutral sphingomyelinase-3 (nSMase3), a nucleic acid encoding said nSMase3, a vector containing said nucleic acid, and cells and non-human organisms transformed or transfected with said nucleic acid sequence or vector. The invention furthermore relates to the use of said nSMase3 as pharmaceutical or diagnostic agent. Test systems for candidate active agents for their therapeutic potential in diseases connected with nSMase3 are also provided.