P.Gly61Glu and P.Arg368His Mutations in CYP1B1 that Cause Congenital Glaucoma may be Relatively Frequent in Certain Regions of Gilan Province, Iran

PURPOSE: To perform a population-based screening of four CYP1B1 mutations—p.Gly61Glu, p.Arg368His, p.Arg390His, and p.Arg469Trp—in the province of Gilan, Iran. Previous studies have shown that CYP1B1 is a cause of disease in approximately 70% of Iranian patients with primary congenital glaucoma (PCG), and that these four mutations constitute the majority of CYP1B1 mutated alleles. The carrier frequencies may even justify premarital screenings. METHODS: DNA was extracted from the blood samples of 700 individuals recruited in a population-based epidemiology study in Gilan. Screenings were performed using polymerase chain reaction protocols based on restriction fragment length polymorphism or the amplification-refractory mutation system. For confirmation, the DNA of individuals with mutations was sequenced using the Sanger protocol. RESULTS: Five individuals carried the p.Gly61Glu mutation, and seven carried the p.Arg368His mutation. The p.Arg390His and p.Arg469Trp mutations were not observed in any of the 700 individuals screened. The mutations were not geographically randomly distributed in Gilan; four of the p.Gly61Glu-harboring individuals were from Talesh, and six of the p.Arg368His-harboring individuals were from the eastern regions of Gilan. CONCLUSION: The frequency of individuals who carry either p.Gly61Glu or p.Arg368His is relatively high in Gilan, and notably high in certain localities within Gilan. We suggest further screenings be performed to definitively assess the need for implementing measures to encourage screening for p.Gly61Glu and p.Arg368His before marriage in Talesh and the eastern regions of Gilan, respectively. Finally, our assessment showed that regional frequencies of CYP1B1 mutations do not necessarily mirror national frequencies.