1928
Whereas the mechanisms leading to the severe , progressive and specific neurological dysfunctions when this gene is mutated still remain to be elucidated , a series of different mouse models have been generated , bearing different Mecp2 mutation .
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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