[1] Northwest Minzu Univ, Biomed Res Ctr, Lanzhou, Peoples R China
[2] Erasmus MC Univ Med Ctr, Dept Gastroenterol & Hepatol, Rotterdam, Netherlands
[3] Erasmus MC Univ Med Ctr, Dept Epidemiol, Rotterdam, Netherlands
[4] Mashhad Univ Med Sci, Sch Med, Dept Genet, Mashhad, Razavi Khorasan, Iran
[5] King Fahad Med City, Res Ctr, POB 59046, Riyadh 11525, Saudi Arabia