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OBJECTIVE To determine the relative effects of genetic and environmental factors in susceptibility to ankylosing spondylitis ( AS ) .
 Disease: ankylosing spondylitis; Disease: AS
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease 
Text: {0} 
Answer:
 Disease: ankylosing spondylitis; Disease: AS