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: Northern blot analysis and sequencing of cloned PCR amplified VLCAD cDNA from four unrelated patients with VLCAD deficiency showed that VLCAD mRNA was undetectable in one patient and that the other three have mutations in both VLCAD alleles .
### Output Text:
Northern blot analysis and sequencing of cloned PCR amplified VLCAD cDNA from four unrelated patients with <span class="disease">VLCAD deficiency</span> showed that VLCAD mRNA was undetectable in one patient and that the other three have mutations in both VLCAD alleles . 