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: Meiotic drive at the myotonic dystrophy ( DM ) locus has recently been suggested as being responsible for maintaining the frequency , in the human population , of DM chromosomes capable of expansion to the disease state .
### Output Text:
Meiotic drive at the <span class="disease">myotonic dystrophy</span> ( <span class="disease">DM</span> ) locus has recently been suggested as being responsible for maintaining the frequency , in the human population , of <span class="disease">DM</span> chromosomes capable of expansion to the disease state . 