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: Myotonic dystrophy , or dystrophia myotonica ( DM ) , is an autosomal dominant multisystem disorder caused by the expansion of a CTG trinucleotide repeat in the 3 untranslated region of the DMPK protein kinase gene on chromosome 19q13 .
### Output Text:
<span class="disease">Myotonic dystrophy</span> , or <span class="disease">dystrophia myotonica</span> ( <span class="disease">DM</span> ) , is an <span class="disease">autosomal dominant multisystem disorder</span> caused by the expansion of a CTG trinucleotide repeat in the 3 untranslated region of the DMPK protein kinase gene on chromosome 19q13 . 