VSX1 gene analysis in keratoconus.

Purpose: To screen the visual system homeobox 1 (VSX1) gene in keratoconus patients.

Methods: The enntire coding region of VSX1, including intron-exon boundaries were amplified in keratoconus cases (n=50) and controls (n=50). All sequences were analyzed against the ensemble sequence (ENSG00000100987) for VXS1.

Results: Sequencing analysis showed four alterations (p.A182A, p.R217H, p.P237P, and g.25059612C>T) in VSX1 of which g.25059612C>T (in intron 2) was found to be novel. Of these four, p.A182A and p.P237P were present in both cases as well as controls while p.R217H and g.25059612C>T were limited to cases only. All these changes were non-pathogenic.

Conclusions: In our study no pathogenic VSX1 mutation was identified. The role of VSX1 in the pathogenesis of keratoconus is still controversial. VSX1 mutations are responsible for a very small fraction of all observed keratoconus cases. The absence of pathogenic mutations in VSX1 in our patients indicates that other genetic loci like 13q32 as suggested by a recent study may be involved in the pathogenesis of this disorder.