2837
The mutation , which causes loss of an HphI site and changes amino acid 155 from threonine to isoleucine , was absent from 108 normal chromosomes .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Disease 
Text: {0} 
 Entities:  
Answer:
 None