MUC5B and congenital rubella syndrome: Regarding MUC5B, 9 out of 14 articles reported increased expression in CRS patients [32,37,40,41,44,65,67,72,73], 4 reported no significant difference [68,69,74,75], and a single article reported a decrease in MUC5B expression in the CRS group compared to the control group [70].