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: Alleles positively associated with IDDM in INS region were the same as those positively - associated with IDDM in Caucasian population , although positively - associated alleles are very common ( allele frequencies > 0 . 9 ) in the Japanese general population .
### Output Text:
Alleles positively associated with <span class="disease">IDDM</span> in INS region were the same as those positively - associated with <span class="disease">IDDM</span> in Caucasian population , although positively - associated alleles are very common ( allele frequencies > 0 . 9 ) in the Japanese general population . 