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: These ocular findings are consistent with observations in ND patients and the generated mouse line provides a faithful model for study of early pathogenic events in this severe X - linked recessive neurological disorder . .
### Output Text:
These ocular findings are consistent with observations in <span class="disease">ND</span> patients and the generated mouse line provides a faithful model for study of early pathogenic events in this severe <span class="disease">X - linked recessive neurological disorder</span> . . 