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Only recently have we realized the importance of DNA copy number variants (CNVs) in the etiology of complex disease. This manuscript by Davis et al. (1183) reports the identification of 11 rare CNVs in primary open angle glaucoma. CNVs can be difficult to detect and such studies are plagued by false positives. The authors addressed this difficulty through the use of multiple software platforms to identify CNVs. GWAS arrays from 400 primary open angle glaucoma cases and 500 controls were analyzed with PennCNV and either CNAG or dChip software. CNVs called with two different software platforms were then subjected to validation with quantitative real-time PCR or array comparative genomic hybridization. Both duplications and deletions were identified. The genes involved have a variety of functions, ranging from kinases to transcription factors, to nucleotidases. Interestingly, several CNVs were found in the GLC1M linkage locus for juvenile open angle glaucoma, and others map to the GLC1K locus. All of the identified CNVs were quite rare, with the most common (deletion of TULP3) being detected in only 1% of cases analyzed. Replication studies are needed in additional glaucoma cohorts to confirm these findings and functional studies would help to understand how these copy number variants might be involved in the etiology of glaucoma.