Screening of the Seed Region of MIR184 in Keratoconus Patients from Saudi Arabia

Micro-RNAs (miRNAs) are regulators of gene expression that control various biological processes. The role of many identified miRNAs is not yet resolved. Recent evidence suggests that miRNA mutations and/or misexpression may contribute to genetic disorders. Point mutations in the seed region of MIR184 have been recently identified in Keratoconus (KC) patients with or without other corneal and lens abnormalities. We investigated mutations within MIR184 in KC patients from Saudi Arabia and examined the relative expression of miR-184 and miR-205 in human cornea. Ethnically matched KC cases (n = 134) were recruited and sequencing was performed using PCR-based Sanger sequencing and analyzed using the Sequencher 5.2 software. Expression of miR-184 and miR-205 was profiled in postmortem unaffected ocular tissues obtained from donors with no history of ocular diseases. miR-184 expression was 15-fold higher than that of miR-205 in cornea samples. No mutation(s) within the screened genomic region of MIR184 in KC cases was detected. This suggests that mutation in MIR184 is a rare cause of KC alone and may be more relevant to cases of KC associated with other ocular abnormalities. The increased expression of miR-184 versus miR-205 in normal cornea samples implies a possible role of miR184 in cornea development and/or corneal diseases.