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: We report about Dr . Kniest , who first described the condition in 1952 , and his patient , who , at the age of 50 years is severely handicapped with short stature , restricted joint mobility , and blindness but is mentally alert and leads an active life .
### Output Text:
We report about Dr . Kniest , who first described the condition in 1952 , and his patient , who , at the age of 50 years is <span class="disease">severely handicapped</span> with <span class="disease">short stature</span> , <span class="disease">restricted joint mobility</span> , and <span class="disease">blindness</span> but is mentally alert and leads an active life . 