VSX1 and keratoconus: A single study, using a gene candidate approach, showed three non-synonymous substitutions (Leu68His, Arg131Ser, and Asp105Glu) in VSX1 gene segregating with the phenotype in patients from the Northeast of Brazil who presented with sporadic KC, suggesting a role for this gene in KC development.[35] However, no additional studies are available in Brazil regarding polymorphisms in other genes whose involvement in KC has already been described.