Association of <i>Lysyl oxidase (LOX)</i> polymorphisms with the risk of Keratoconus in an Iranian population

<div><p></p><p><i>Background</i>: Keratoconus is a connective tissue-related eye disease with unknown etiology that causes the loss of visual acuity. Lysyl oxidase (LOX) is an amine oxidase that catalyzes the covalent cross-link of collagens and elastin in the extracellular environment, thus determining the mechanical properties of connective tissue. The current study aimed to investigate the possible associations between two <i>LOX</i> polymorphisms, rs1800449 and rs2288393, and susceptibility to keratoconus.</p><p><i>Methods</i>: A total of 262 Iranian subjects including 112 patients with keratoconus and 150 healthy individuals as controls were recruited. Genotyping for the <i>LOX</i> variants was performed using allele-specific PCR.</p><p><i>Results</i>: A significant difference was found between two groups regarding allelic and genotyping distribution of <i>LOX</i> polymorphism at position rs1800449 G>A. The frequency of AA and GA + AA genotypes were increased in patients compared to controls (17% versus 8% and 62.5% versus 50%, respectively), showing a statistically significant difference (OR = 2.827, 95% CI: 1.251–6.391, <i>p</i> = 0.012). The A allele was associated with an increased risk for keratoconus, with the frequency of 39.9% and 29% in patients and controls, respectively (OR = 1.614, 95% CI: 1.119–2.326, <i>p</i> = 0.011). Furthermore, the haplotype analysis revealed that the rs1800449G/rs2288393C is a protective factor against keratoconus (OR = 0.425, 95% CI = 0.296–0.609, <i>p</i> = 0.001). Conversely, the +473A/rs2288393C (OR = 3.703, 95% CI = 2.230–6.149, <i>p</i> = 0.001) and +473G/rs2288393G (OR = 15.48, 95% CI = 3.805–63.03, <i>p</i> = 0.001) haplotypes were identified as risk factors for keratoconus.</p><p><i>Conclusion</i>: Our study demonstrated that the LOX rs1800449 genotypes (AA and GA + AA) and allele (A) appears to confer risk for susceptibility to keratoconus.</p></div>