Dermal melanocytosis (DM) is described as the presence of ectopic melanocytes in the dermis and could be a normal cutaneous finding. Mongolian spots are blue or slate-gray macular lesions occurring most commonly in the sacral area but also found over posterior thighs, legs, back, and shoulders. However, diffuse DM or extensive Mongolian spots must be considered as an early sign of neurometabolic diseases, in particular lysosomal storage disorders. Mongolian spots usually fade during the first few years of life, but they occasionally persist. Those associated with inborn error of metabolism error of metabolism present no sign of resolution and may also become heavier in their colors. The most common lysosomal storage disease associated with generalized Mongolian spots are Hurler syndrome followed by GM1 gangliosidosis type 1. An association with Niemann-Pick disease, Hunter syndrome, mannosidosis, MPS VI and sandhoff disease was also reported.