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: This correction of the defects in A - T cells provides further evidence of the multiplicity of effector functions of the ATM protein and suggests possible approaches to gene therapy . .
### Output Text:
This correction of the defects in <span class="disease">A - T</span> cells provides further evidence of the multiplicity of effector functions of the ATM protein and suggests possible approaches to gene therapy . . 