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: Mutations in the COL3A1 gene have been implicated as a cause of type IV Ehlers - Danlos syndrome , a disease leading to aortic rupture in early adult life .
### Output Text:
Mutations in the COL3A1 gene have been implicated as a cause of <span class="disease">type IV Ehlers - Danlos syndrome</span> , a disease leading to <span class="disease">aortic rupture</span> in early adult life . 