Genetic variants associated with development of pseudoexfoliation syndrome

Pseudoexfoliation syndrome (PEXS) is a late-onset disorder in which fibrillar material accumulates at abnormally high concentrations mainly in the anterior segment of the eye. PEXS is the most common cause of secondary glaucoma, which can ultimately lead to blindness and is associated with a higher risk of cataract and serious complications following different types of intraocular surgery. Although PEXS clearly has a genetic component, it remains poorly explored. In our genome-wide association study, we searched for an association of genetic variants with this disorder among older Poles with PEXS without glaucoma. A total of 209 individuals including 103 PEXS patients without glaucoma and 106 perfectly (age- and gender-) matched controls were recruited for the study. Genomic DNA was extracted from whole blood treated with EDTA. DNA samples that passed quality control tests were combined according to diagnosis and gender at equimolar concentrations to obtain 10-DNA sample pools. A total of 10 DNA pools were prepared for each of the two groups (control and PEXS), seven for women and three for men. Please note that no data processing was applied and thus only theta values from unprocessed file were provided in the 'Matrix_signal_intensities.txt' file. The main reason for not normalizing the data was that it was derived from pooled samples. Data normalization algorithms were in general optimized for genotype calling (which is impossible for these samples), and thus may introduce possible artifact introduction. Thus "the less the better" approach was made with the data analysis. PCA hasn't revealed any considerable stratification. Raw theta values were used as an input for Student's t-test. Clusters of significant probes were selected for validation in individual patients.