In the sentence extracted from biomedical literature, identify all the disease entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="disease"> to denote a disease.

### Input Text: In vitro expression of mutant cDNA clones demonstrated that all of these mutations led to a deficiency of ASPA and should therefore result in Canavan disease . .
### Output Text:
In vitro expression of mutant cDNA clones demonstrated that all of these mutations led to a <span class="disease">deficiency of ASPA</span> and should therefore result in <span class="disease">Canavan disease</span> . . 