Correspondence to:Chun-Tao Lei. Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan Province, China. hblct@163.com Correspondence to: Bo Gong. Sichuan Provincial Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu 610072, Sichuan Province, China. gongbo2007@hotmail.com