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: Phenotypic characterization of individuals with 30 - 40 CAG repeats in the Huntington disease ( HD ) gene reveals HD cases with 36 repeats and apparently normal elderly individuals with 36 - 39 repeats .
### Output Text:
Phenotypic characterization of individuals with 30 - 40 CAG repeats in the <span class="disease">Huntington disease</span> ( <span class="disease">HD</span> ) gene reveals <span class="disease">HD</span> cases with 36 repeats and apparently normal elderly individuals with 36 - 39 repeats . 