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: To help clarify the physiological roles of the ATM protein , we disrupted the ATM gene in mice through homologous recombination .
### Output Text:
To help clarify the physiological roles of the ATM protein , we disrupted the ATM gene in mice through homologous recombination . 