Background: Keratoconus normally occurs as a sporadic disease.Although different studies have found sequence variants of visual system homeobox 1 (VSX1) gene associated with keratoconus in humans, no research detected VSX1 sequence variant in sporadic keratoconus patienets from China.To investigate the possibility of VSX1 gene as a candidate susceptibility gene for Chinese patients with sporadic keratoconus, we performed a sequence screening of VSX1 gene in unrelated patients with keratoconus from China.Methods: Genomic DNA was obtained from the leukocytes in peripheral venous blood of 50 patients with sporadic keratoconus and 50 control subjects without the ocular disorder.Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and direct DNA sequencing technology were used for detection of sequence variant in five exons and the splice region of intron of VSX1 gene.The sequencing results were analyzed using DNAstar software.Results: One novel missense heterozygosity sequence variant (p.Arg131Pro) was found in exon 1 of VSX1 gene in one keratoconus patient.Another heterozygosity sequence variant (p.Gly160Val) in exon 2 was found in two keratoconus patients.And the p.Arg131Pro and p.Gly160Val were not detected in the control subjects.In intron 3 of VSX1 gene, one c.8326G>A nucleotide substitution (including heterozygosity and homozygosity change) was discovered.The frequency of c.8326G>A variation in patients and controls showed no statistically significant difference, so it belonged to single nucleotide polymorphism (SNP) of VSX1 gene.Conclusions: In this research, we added one novel missense sequence variation (p.Arg131Pro) in the coding region of VSX1 gene to the existing repertoire of VSX1 coding variations observed in patient with sporadic keratoconus from China.Our study suggests that VSX1 sequence variant might be involved in pathogenesis of sporadic keratoconus but its precise role in disease causation needs further investigation.