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 keeping with the nature of this mutation , various antibodies directed against the ATM protein failed to defect this protein in patient cells .
### Output Text:
In keeping with the nature of this mutation , various antibodies directed against the ATM protein failed to defect this protein in patient cells . 