ExploringWNT2Polymorphisms in Comitant Strabismus: A Genetic Association Study

Abstract

AbstractBackgroundStrabismus is a complex oculomotor condition characterized by a misalignment of the visual axis. The genetics of strabismus are poorly defined although a few candidate genes have been identified, among which is the WNT2 gene. Our study was designed to assess the association of single nucleotide polymorphisms (SNPs) ofWNT2in Pakistani strabismus patients.MethodsA total of six SNPs, three intronic and three in the 3’ untranslated region, were screened in the current study. Logistic regression was performed using a dominant, recessive and additive model to determine the association of SNPs with strabismus and its clinical subtypes: esotropia and exotropia. Furthermore, haplotype analysis was performed.ResultsRegression analysis revealed an association of rs2896218, rs3779550, rs2285544 and rs4730775 with strabismus under the dominant model. When analyzed separately, rs2896218 and rs2285544 were found to be associated with both esotropia and exotropia, while rs4730775 was significantly associated only with exotropia under the dominant model. Based on clinical parameters, rs2896218, rs2285544 and rs4730775 were also found to be associated with the group of strabismus patients who were diagnosed at birth, but not in the group of patients who were diagnosed later in life. Haplotype analysis revealed that the haplotype A T T (corresponding to rs2896218, rs3779550 and rs2285544) was significantly more prevalent in the strabismus group.ConclusionOverall, the results of the present study suggests an association ofWNT2polymorphisms with strabismus and its subtypes in the Pakistani population, though further studies are needed to elucidate their role in strabismus etiology.What is already known on this topicStrabismus is a common oculomotor condition with a genetic component.WNT2has been identified as a candidate gene for comitant strabismus.What this study addsTwoWNT2polymorphisms not previously reported have been found to be associated with strabismus.There are genetic variations between clinical subtypes of strabismus (esotropia and exotropia).WNT2polymorphisms are associated with age at the time of diagnosis and family history.Combinations of different alleles (haplotypes) are associated with the disease.How this study might affect research, practice or policyOur study adds to the limited genetic data for strabismus and suggests further studies on the role ofWNT2in strabismus causation.