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: The molecular basis of C7 deficiency has been investigated in two Irish families and a number of Israeli families of Moroccan Sephardic Jewish origin .
### Output Text:
The molecular basis of <span class="disease">C7 deficiency</span> has been investigated in two Irish families and a number of Israeli families of Moroccan Sephardic Jewish origin . 