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: In addition , we tested genetic linkage to the SJS locus on chromosome 1 in one family with two affected sibs .
### Output Text:
In addition , we tested genetic linkage to the <span class="disease">SJS</span> locus on chromosome 1 in one family with two affected sibs . 