1868
Although MHC genes , including HLA - B27 , contribute only 20 - 50 % of the genetic risk for the disease , no non - MHC gene has yet been convincingly demonstrated to influence either susceptibility to the disease or its phenotypic expression .
 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