Carrier Frequency of P.R368h in Glaucoma Causing Gene Cyp1b1 May Justify Pre-Marital Screenings in Eastern Guilan

Background and aim: glaucoma is a major cause of blindness. primary congenital glaucoma (pcg) is the most severe form of glaucoma. genetic factors significantly contribute to its etiology, and cyp1b1 is its most important causative gene. in the first study on the genetics of pcg among iranians, it was shown that mutations in cyp1b1 were the cause of disease in approximately 70% of 100 patients studied. also, among 19 different mutations identified, four were most frequent. additionally, the western and north western regions of iran had the highest prevalence of pcg, and the distribution of the mutations in various regions of iran differed. guilan was a province with high pcg prevalence. a subsequent study on 700 patients from guilan, suggested that mutated alleles that are causative of p.g61e and p.r368h were frequent specifically in, respectively, talesh and eastern regions of guilan. here, we aimed to get a more accurate estimate of carrier frequencies of these mutations in these regions in order to consider need for pre-marital screenings. methods: in order to achieve a carrier frequency estimate with maximum error of 2%, 1000 individuals from talesh and 3000 from eastern regions of guilan needed to be screened for the respective mutations. individuals were recruited based on cluster sampling. dna was extracted from saliva samples. the c.182g>a causative mutation of p.g61e was screened in the talesh samples using an rflp protocol. the c.1103g>a mutation causative of p.r368h was screened using an arms pcr protocol. statistical analyses were done using openepi. results: nine individuals among 1036 from talesh were shown to be carriers of the p.g61e mutation, and 73 among 3029 individuals from eastern regions of guilan were carriers of the p.r368h mutation. these figures indicate a carrier frequency of 0.0086 (95% confidence interval: 0.0045 – 0.0164) for p.g61e in talesh, and 0.024 (95% confidence interval: 0.019 – 0.030) for p.r368h in east of guilan. conclusion: the carrier frequencies calculated are within ranges previously assessed, but with significantly improved confidence intervals. based on results of premarital screenings of thalassemia causing mutations on incidence of this disease in iran, premarital screenings of the p.r368h may be justified.