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: Six years on , we review 100 reports of intragenic WT1 mutations and examine the accompanying clinical phenotypes .
### Output Text:
Six years on , we review 100 reports of intragenic WT1 mutations and examine the accompanying clinical phenotypes . 