Updated project metadata. In this study we present data from the only available post-mortem mucolipidosis type IV (MLIV) patient. We characterise the brain pathology of the MLIV patient and compare it to pathology from the mice model of MLIV. Moreover, we characterise the proteins found in the MLIV patient CSF and compare it to the mice MLIV CSF. We define possible biomarkers for this devastating disease.