24404
Furthermore , characteristics of 5 - Htt and Tph2 KO mice are covered together with association studies on human variants of 5 - HTT and TPH2 in emotional regulation .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None