Exploration Of The MYOC Gene Mutation In A Family With Primary Open-angle Glaucoma

Purpose: To search for the MYOC mutation of primary open-angle glaucoma (POAG) in a large family in Fujian Province and to investigate the relationship of the genotype and the phenotype.Patients: We performed comprehensive ophthalmologic examinations for a primary open-angle glaucoma family of five generations which includes 144 members according to the diagnostic criteria of primary open-angle glaucoma. There are 17 members were confirmed to have POAG , 1 with high cup disc ratio was considered as POAG suspect, and the remaining 126 were asymptomatic. 12 available blood samples were obtained and 3 of them were confirmed to have POAG, 1 was considered as POAG suspect, and the remaining 8 were asymptomatic. All the 3 patients had already accepted surgery therapy and the result is not well.Methods:(1)3ml blood samples were collected from 12 family members including POAG patients and unaffected members.(2)Genomic DNA was extracted and purified from the peripheral leukocytes by using Wizard Genomic DNA Purification kit.(3)3 paires of specific primers were designed according to the references.(4)Genomic DNA of the 12 family members was amplified using polymerase chain reaction. Then the production was purified and sequenced forward and inverse. ( 5 )Investigate the relationship of the genotype and the phenotype according to the clinical symptoms of the patients.Results: (1)We identified one MYOC mutation in 4 of 12 family members and 3 of them were confirmed to have POAG, 1 was considered as POAG suspect, and the remaining 8 were asymptomatic.(2)The MYOC gene mutation c.G1099A , Gly367Arg, was detected by sequencing the PCR production. The transition at codon 367 produced the mutation of glycine to arginine and the structural and functional alteration of the corresponding protein.Conclusions: Gly367Arg mutation of MYOC is likely responsible for the etiology of POAG in this large family. The phenotype of this mutation is characterized by high IOP, high vertical cup-to-disc ratios and insensitivity to surgery. MYOC gene mutation could cause structural and functional alteration of the corresponding protein which is exactly one of the risk factors of POAG.