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: The I66M mutation in the wild - type GALC cDNA ( I289 ) had normal activity , but when this mutation and the V289 polymorphism were introduced into the same allele , it had decreased activity .
### Output Text:
The I66M mutation in the wild - type GALC cDNA ( I289 ) had normal activity , but when this mutation and the V289 polymorphism were introduced into the same allele , it had decreased activity . 