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: However , the overall prevalence of definite CHD was 21 % in men with mutations and 16 % in men without mutations .
### Output Text:
However , the overall prevalence of definite <span class="disease">CHD</span> was 21 % in men with mutations and 16 % in men without mutations . 