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: To determine the mechanism for increased activity of the LA variant , we compared GALT mRNA , protein abundance , and enzyme thermal stability in lymphoblast cell lines of D and LA phenotypes with comparable genotypes .
### Output Text:
To determine the mechanism for increased activity of the LA variant , we compared GALT mRNA , protein abundance , and enzyme thermal stability in lymphoblast cell lines of D and LA phenotypes with comparable genotypes . 