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The CYP1A1 gene is related to the generation of secondary metabolites that are capable of inducing DNA damage. The CYP1A1m1 polymorphism has been examined in many studies, and is located in a region near loci that have been linked to glaucoma, including the locus GLC1I. As a result, this polymorphism has been related to several diseases that are influenced by exposure to xenobiotic as well as primary open-angle glaucoma. We compared the prevalence of the CYP1A1m1 polymorphism in 152 Brazilian patients, 100 patients with primary open-angle glaucoma, and 52 normal controls using restriction fragment length polymorphism analysis. The frequency of the homozygous wild-type (w1/w1) CYP1A1 gene among patients with primary open-angle glaucoma (N = 100) was 16%, for genotype w1/m1, the frequency was 77%, and for m1/m1 it was 7%. Among the control group (N = 52), the frequency of the homozygous wild-type (w1/w1) CYP1A1 gene was 54%, the frequency of w1/m1 was 46%, and the frequency of m1/m1 was 0%. The presence of the CYP1A1m1 polymorphism may interfere with xenobiotic metabolism and exacerbate direct or indirect damage to the optic nerve. These CYP1A1m1 polymorphisms may be risk factors for primary open-angle glaucoma.

In this study, we evaluated the genotype profile of GSTM1 and GSTT1 polymorphisms in patient carriers of primary open-angle glaucoma in the population of Goiânia, GO, Brazil. This case-control study included 100 Brazilian patients with glaucoma and 53 patients without glaucoma. Blood samples were genotyped for polymorphisms in GST genes using polymerase chain reaction-based methods. Polymorphism frequencies were compared using the X(2) test and odds ratio (α = 0.05). The GSTM1-present genotype was 40% in the glaucoma group and 71.6% in the control group, while the GSTM1 null genotype was 60 and 28.3% in the same groups, respectively. The GSTT1-present genotype was 52% in the primary open-angle glaucoma group and 66% in the control group; the null genotype was 48% in the case group and 34% in the control group. The GSTM1 null genotype was more frequent in the glaucoma group than in the control group (P = 0.0004; odds ratio = 6.7; 95% confidence interval = 2.7- 20.3). The combined GSTM1 null and GSTT1-present genotypes were more frequent in the primary open-angle glaucoma group compared to the control group (P = 0.02; odds ratio = 3.1; 95% confidence interval = 1.2-7.9).

Primary open-angle glaucoma (POAG) is characterized by loss of retinal ganglion cells, optic nerve damage and irreversible loss of visual field. Glaucoma is the second leading cause of blindness worldwide. It was estimated that in 2010 there were about 60.5 million glaucoma cases worldwide; among these patients, 4.5 million will become bilaterally blind. Glutathione S-transferases (GST) are a group of drug-metabolizing enzymes of phase-II that act in the detoxification of xenobiotics and inactivate end-products formed as secondary metabolites during oxidative stress. Through PCR amplification, we analyzed the GSTM1 gene in DNA samples from 25 patients with POAG and 25 controls; 14 of the patients presented the GSTM1 gene null polymorphism while only eight of the control group had this gene.Although the POAG patients had a higher frequency of GSTM1, the difference was not significant (P = 0.0874); this lack of significance could be due to the small sample size.

Primary open angle glaucoma (POAG) is the most common type of glaucoma. The p53 codon 72 Arg-Pro (CGC to CCC) polymorphism of exon 4 affects various biological properties; recently, it was reported that this polymorphism affects the ability to induce apoptosis in vitro. Various genotypes have been found to be significantly associated with POAG. We examined the distribution of this polymorphism in 104 unrelated POAG patients and in 58 normal healthy individuals without history of POAG at the Pronto Clínica de Olhos in Goiânia, Brazil. The controls were recruited among individuals undergoing ophthalmological examination. Their genomic DNA was analyzed for p53 gene codon 72 polymorphism by polymerase chain reaction. The Arg72 allele was more common than the Pro72 allele in both groups. There was no significant difference in the distribution of the codon 72 polymorphism between groups (p= 0.3311). The genotype distribution in the POAG group was 23.07 Arg homozygote, 75 heterozygote, and 1.93% Pro homozygote, while in the control group it was 31.04 Arg homozygote, 68.96 heterozygote, and 0% Pro homozygote. We concluded that the p53 codon 72 Arg/Pro polymorphism is not associated with glaucoma in Brazilian patients.

Pterygium is a disease of unknown origin and pathogenesis that can be vision threatening. Several researchers believe that pterygium is UV-related and that abnormal expression of p53 protein and infection with human papillomavirus (HPV) are risk factors for pterygium, but their experiments have been inconclusive. We investigated its relation with p53 protein expression, p53 gene codon 72 polymorphism and infection with HPV DNA. Pterygial samples were obtained from 36 patients; 21 normal conjunctival samples were used as controls. Expression of p53 protein was studied by immunohistochemistry, using the antibody DO-7. Analysis for the p53 genotype was made by polymerase chain reaction, using specific primers for the arginine and proline alleles, and an analysis for HPV was made of the pterygium patients and control group. Fourteen of the 36 pterygial specimens were positive for abnormal p53 expression. Thirty-one of the patients were heterozygotic and three were homozygotic for the proline allele; two were homozygotic for the arginine allele; in the control group 12 of 21 were heterozygotic and seven of these 21 were homozygotic for the proline allele; two were homozygotic for the arginine allele. Twenty-one of the pterygium patients were positive for HPV; HPV type 1 was found in nine of these, type 2 in seven and both types in five. Only two of the 21 controls had HPV; both had type 16. We suggest that abnormal expression of p53, p53 codon 72 polymorphisms and HPV DNA are required co-factors for the development of pterygium.