Arisawa T, et al. – Here, the authors examine whether single nucleotide polymorphisms in maf protein K (MAFK), which encodes the MAFK, lead to increased susceptibility to ulcerative colitis (UC) in the Japanese population. They present the first evidence that MAFK genetic polymorphisms are significantly correlated with susceptibility to UC development. Specifically, for the development of UC, rs4268033 is closely associated with an increased risk.