873
Current data also support the emerging role played by Mecp2 in mediating the epigenetic programming induced by early life events and indicate that , in the absence of functional MeCP2 , programming of the central nervous system in response to early environmental stimuli is abnormally regulated .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None