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: Analysis of DMAHP expression in the cells of DM patients with loss of the hypersensitive site revealed a two - to fourfold reduction in steady - state DMAHP transcript levels relative to wild - type controls .
### Output Text:
Analysis of DMAHP expression in the cells of <span class="disease">DM</span> patients with loss of the hypersensitive site revealed a two - to fourfold reduction in steady - state DMAHP transcript levels relative to wild - type controls . 