Association of IL4 rs2070874, FoxP3 rs3761548 Polymorphisms with Keratoconus in Algeria.

Wafaa Meteoukki,Amine Derdour,Meriem Samia Aberkane,Abdelillah Chiali,Aicha Idder,Mostefa Fodil,Hadjira Ouhaibi Djellouli,Meriem Abdi,Nawel Adda Negaz,Sarah Lardjam Hetraf,Ahlem Djelti Messal,Nesrine Rahmoun,Faouzia Zemani-Fodil

doi:10.18502/jovr.v16i4.9745

Abstract

Purpose The aim of this case–control study was to determine the impact of environmental factors on the predisposition to develop keratoconus in a sample of Western Algerian population. Subsequently, we were interested in the implication of two single nucleotide polymorphisms (SNPs) IL4 rs2070874 and FOXP3 rs3761548, previously described as contributing to the occurrence of allergy, in the development of keratoconus.MethodsThe study included 70 unrelated KC cases and 70 controls originating from Western Algeria. DNA genotyping was done using predesigned probe-based allelic discrimination TaqManⓇ assays. Allele and genotype frequencies were compared between the cases and controls by Chi-square test and odds ratios with 95% confidence intervals.ResultsA significant association between risk factors such as family history, atopy, eye rubbing, and the development of keratoconus was found in our sample. Smoking would provide a protective effect against the pathology. No statistically significant differences were found in the allele and genotype frequencies between cases and controls neither for IL4 rs2070874 nor for FOXP3 rs3761548.ConclusionOur study provides, for the first time, a clear demonstration of the absence of association of the allergy-associated IL4 and FOXP3 polymorphisms with KC in a sample from Western Algerian population.

Highlights

Keratoconus (KC) is a degenerative bilateral corneal dystrophy characterized by gradual thinning of the cornea leading to a loss of visual acuity
The etiology of KC is not clearly established, genetic and environmental factors such as allergy or eye rubbing seem necessary for disease expression,[4] despite the positive associations found between atopy and KC.[5,6,7]
We were interested in the most discriminating risk factors; we observed a clear significant difference between cases and controls concerning atopy, eye rubbing with a high number of cases than controls exposure to cigarette smoke as risk factor but with a large number of controls than cases (P = 1×10−6)

Summary

Introduction

Keratoconus (KC) is a degenerative bilateral corneal dystrophy characterized by gradual thinning of the cornea leading to a loss of visual acuity. The etiology of KC is not clearly established, genetic and environmental factors such as allergy or eye rubbing seem necessary for disease expression,[4] despite the positive associations found between atopy (allergy, asthma, eczema) and KC.[5,6,7] No study has focused on the association between KC and polymorphisms in inflammatory mediators genes of these immune disorders. Interleukin 4 is a pleiotropic cytokine produced by activated T-lymphocyte and mast cells.[8] This cytokine plays a major role in type 2 immune responses characterized by the production of immunoglobulin E (IgE) and immunoglobulin G1 (IgG1).[9] IgE is strongly implicated in atopic and allergic diseases.[10] Several genetic variants in the IL4 gene and its receptor IL4-R have been found associated with allergic rhinitis (AR).[11] The IL4 rs2070874 has been reported as associated with asthma and atopy in several studies.[12, 13] HaiJun Yang performed a meta-analysis and found that this polymorphism is correlated with increased asthmatic risk.[14]

Methods

Results

Conclusion