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: Although the DM mutation was identified more than five years ago , the pathogenic mechanisms underlying this most prevalent form of hereditary adult neuromuscular disease remain elusive .
### Output Text:
Although the <span class="disease">DM</span> mutation was identified more than five years ago , the pathogenic mechanisms underlying this most prevalent form of hereditary adult <span class="disease">neuromuscular disease</span> remain elusive . 