microRNAs as markers of congenital aniridia

Subjects with congenital aniridia often develop aniridia‐associated keratopathy (AAK), which is related to limbal stem cell insufficiency. Loss of limbal epithelial stem cell function results in corneal inflammation and neovascularization, and several subjective symptoms. MicroRNAs (miRNAs) are approximately 22 nt long non‐coding RNA molecules capable of regulating gene expression at the post‐transcriptional level. It is of interest to investigate the expression of microRNAs and their possible effect on AAK development, as deeper understanding of their function in limbal epithelial cells could help in designing new therapeutic approaches of AAK. Previous studies verified deregulated miRNAs in conjunctival cells of aniridia subjects, among others miR‐204‐5p and miR‐7150, which are more deregulated in mild cases of AAK. In addition, numerous studies suggest that miRNAs regulate genes involved either directly or indirectly in inhibition or promotion of pathological angiogenesis of the cornea. Several pathways, including JAK–STAT, focal adhesion, Hippo, WNT and PI3K‐AKT signalling pathways, could potentially play a role. In limbal epithelial cells of aniridia subjects, deregulation of miR‐138‐5p may play a role, which is involved in the regulation of cell differentiation and migration and in Hippo, Wnt, Focal adhesion cAMP and p53 signalling pathways.