The association of the AC/GA combined heterozygotes with male POAG patients is probably because of the presence of a higher number of XRCC1 heterozygotes (i.e., G/A) in POAG and not because of the AC heterozygotes of XPD. This combined genotype is also found to be present at a higher frequency in the affected males from the families, though the difference is statistically non-significant but that is probably due to the smaller sample size of the affected males in the families. This evidence concerns the gene XRCC1 and open-angle glaucoma.