Myocilin mutations are not a major cause of primary congenital glaucoma in Iranian patients

To assess the frequency of mutations in the Myocilin [MYOC] gene in Iranian patients affected with primary congenital glaucoma [PCG]. The individuals evaluated herein are among the larger cohort of 100 patients who had previously been screened for CYP1B1 mutations. Eighty subjects carried mutations in CYP1B1, but the remaining 20 patients who did not, underwent screening for MYOC mutations for the purpose of the study. MYOC exons in the DNA were polymerase chain reaction [PCR] amplified and sequenced. Sequencing was performed using PCR primers, the ABI big dye chemistry and an ABI3730XL instrument. Sequences were analyzed by comparing them to reference MYOC sequences using the Sequencher software. Four MYOC sequence variations were observed among the patients, but none of them were considered to be associated with disease status. Three of these variations were single nucleotide polymorphisms already reported not to be disease causing, the fourth variation created a synonymous codon and did not affect any amino acid change. In this cohort, MYOC mutations were not observed in any Iranian subject with PCG. It is possible that in a larger sample, a few subjects carrying disease causing MYOC mutations could have been observed. But our results show that the contribution of MYOC to PCG status in Iran is small if any

Sex bias in primary congenital glaucoma patients with and without CYP1B1 mutations

To investigate variations in sex ratio among Iranian primary congenital glaucoma [PCG] patients with and without mutations in the CYP1B1 gene and to evaluate possible clinical variations associated with sex in these two groups. Phenotypical data on 104 unrelated Iranian PCG patients who had previously been screened for CYP1B1 mutations were analyzed. Emphasis was placed on analysis of sex ratios among patients with and without CYP1B1 mutations. In addition to sex, familial and sporadic incidence and clinical features including age at onset, bilateral/unilateral involvement, corneal diameter, intraocular pressure, and cup-disc ratios were compared between these two groups. Information on phenotypical parameters was available for most but not all patients. Among the 93 PCG patients whose sex was recorded, 57 were male [61.3%] and 36 were female [38.7%] [P=0.03]. Patients with CYP1B1 mutations included 37 male [66.1%] and 29 female [43.9%] subjects [P=0.30], while patients without the mutation included 20 [74.1%] male and 7 [25.9%] female individuals [P=0.013]. Our data did not provide conclusive evidence on difference in severity of the disease between those with and without CYP1B1 mutations, nor between the two sexes. Consistent with data on PCG patients from other populations, the overall incidence of PCG in Iran seems to be higher among male subjects. The difference in incidence between the two sexes was not significant among patients whose disease was due to mutations in CYP1B1. The overall higher incidence of PCG among male subjects seems to be attributable to a higher incidence in male patients not harboring CYP1B1 mutations, suggesting that other genes or factors may be involved in manifestation of PCG phenotypes in a sex dependent manner