Accumulation of polyubiquitinated proteins can be indicative of impaired proteolysis through both the ubiquitin-proteasome- and lysosome-systems, and reduced activity of the ubiquitin C-terminal hydrolase UCH-L1 has been noted in the brains of the SD mouse model, as well as in cultured cells from numerous other lysosomal storage disorders patient samples [3]. The gene discussed is UCHL1; the disease is lysosomal storage disease.