Although the amplification of the 12q13–15 region, carrying the MDM2 andCDK4 genes, is used to distinguish WD/DDLPS and ALT from benign lipomas and from other types of liposarcomas, specific aberrations that can be used to distinguish between WDLPS and DDLPS subtypes have not been identified so far. The gene discussed is MDM2; the disease is Wilson disease.