Abstract: Objective · To analyze the correlation between CITED2 gene mutation and situs inversus. Methods · A total of 24 patients with situs inversus and 100 healthy controls were collected. The genomic DNA was isolated their peripheral blood. PCR and Sanger sequecing were employed to analyze the exons of CITED2. The potential effect of the mutation was characterizedthe software Sift, PolyPhen-2, PROVEAN and Mutation Taster. The Y. Zhang laboratory server was used to predict the three-dimensional structure of the protein, and the SWISS-PdbViewer was imported to see the impacts of the mutation on the protein structure. Results · A novel heterozygous CITED2 mutation c.418C>T (p.P140S) was identified in 1 patient with situs inversus, which was absent in all controls. The novel heterozygous p.P140S mutation was predicted to be pathogenicSIFT and Mutation Taster. The SWISS-PdbViewer showed that the mutation p.P140S caused all three hydrogen bonds on the aspartic acid at position 137 to be disconnected, and an abnormal weak hydrogen bond was re-established between the serine at position 140 and the alanine at position 142. Conclusion · The novel heterozygous mutation c.418C>T (p.P140S) may affect the biological activity of CITED2 and may be related to situs inversus.

Key words: situs inversus, CITED2 gene, gene mutation