A study of German glaucoma patients found haplogroup U significantly underrepresented in pseudoexfoliation glaucoma subjects, and a trend for haplogroup U being underrepresented in POAG; however, they did not investigate sex as a variable.28 A second finding in our study was a significantly lower frequency of rare variants in the MT-ND2 gene in cases compared with controls, suggesting a protective effect against POAG. The gene discussed is MT-ND2; the disease is open-angle glaucoma.