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: We provide evidence that not only reduced , but also increased levels of transcriptional regulators can cause developmental defects . .
### Output Text:
We provide evidence that not only reduced , but also increased levels of transcriptional regulators can cause <span class="disease">developmental defects</span> . . 