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: Association studies in two independent samples totaling 505 individuals revealed that the 5 - HTT polymorphism accounts for 3 to 4 percent of total variation and 7 to 9 percent of inherited variance in anxiety - related personality traits in individuals as well as sibships . .
### Output Text:
Association studies in two independent samples totaling 505 individuals revealed that the 5 - HTT polymorphism accounts for 3 to 4 percent of total variation and 7 to 9 percent of inherited variance in <span class="disease">anxiety - related personality traits</span> in individuals as well as sibships . . 