The Role of C21orf91 in Herpes Simplex Virus Keratitis

Background and Objectives: This paper aims to describe the single nucleotide polymorphisms (SNPs) of C21orf91 rs1062202 and rs10446073 in patients with herpetic keratitis by evaluating corneal sub-basal nerves, as well as the density of Langerhans cells (LC) and endothelium cells (EC) during the acute phase of the disease. Materials and Methods: A prospective clinical study included 260 subjects: 70 with herpetic eye disease, 101 with previous history of herpes labialis-but no history of herpetic eye disease-and 89 with no history of any herpes simplex virus (HSV) diseases. All subjects underwent a complete ophthalmological examination including in vivo laser scanning confocal microscopy (LSCM) of the central cornea. C21orf91 rs1062202 and rs10446073 were genotyped using the real-time polymerase chain reaction (PCR) method with the Rotor-Gene Q real-time PCR quantification system. SNPs were determined using TaqMan genotyping assay, according to the manufacturer's manual. Results: The C21orf91 rs10446073 genotype GT was more frequent in the HSV keratitis group, compared with healthy controls (20.0% vs. 7.9%), OR 2.929[1.11-7.716] (p <0.05). The rs10446073 genotype TT was more frequent in healthy controls (12.4% vs. 1.4%), OR 22.0[2.344-260.48] (p <0.05). The rs10446073 genotype GT increased the risk of EC density being less than 2551.5 cell/mm², OR 2.852[1.248-6.515] (p <0.05). None of the SNPs and their genotypes influenced the LC density and corneal sub-basal nerve parameters (p >0.05). Conclusions: Our study reports a new association between herpetic keratitis and human gene C21orf91, with the rs10446073 genotype GT being more common in herpetic keratitis patients and increasing the risk for the disease by a factor of 2.9.