Study On OPTN Gene Mutation In Glaucoma Family With MYOC Gene T455K Mutation

Objective:In 2007, we identified a typical, large primary open angle glaucoma family and named it TJ1 pedigree. A novel disease-causing mutation T455K in myocilin(MYOC) gene was found in this pedigree. In this research, we will investigate the relation between optineurin(OPTN) gene mutation and TJ1 pedigree.Methods:(1) Isolation of the genomic DNA: The genomic DNA was extracted from 19 family members and 50 normal controls blood by using DNA Isolation Kits for Mammalian Blood.(2) Polymerase chain reaction(PCR):All the 13 coding exons of OPTN gene were amplified, including the intron-exon boundaries, in 19 family members by polymerase chain reaction.(3) Single-strand conformation polymorphism(SSCP): The 13 coding exons and their intron-exon boundaries of OPTN gene in 19 family members were screened by the use of single strand conformation polymorphism. The coding exon along with its intron-exon boundary with abnormal strand was screened by the use of single strand conformation polymorphism in 50 normal controls. (4) Purification of the PCR products: The PCR products of the coding exon with abnormal strand were purified using Gel Purification Kits. (5) DNA sequencing of the purified PCR products.Results:Three sequence changes were identified: M98K, R545Q and IVS5+38T>G. M98K was only found in 5 family members, of which there were 2 POAG patients, 1 glaucoma suspect and 2 individuals who had not shown apparently signs of glaucoma. R545Q was found in 3 family members including 1 POAG patient and 2 individuals who had not shown apparently signs of glaucoma, and was found in 5 normal controls. IVS5+38T>G was detected in 12 family members including 5 POAG patient, 1 glaucoma suspect and 6 individuals who had not shown apparently signs of glaucoma, and was detected in 30 normal controls.Conclusion:(1) The hereditary modality of TJ1 pedigree is autosomal dominant heredity. (2) Both MYOC gene and OPTN gene may be involved in the pathogenesis of POAG in TJ1 pedigree. MYOC gene is pathogenic gene in TJ1 pedigree, whereas OPTN gene may play a regulative role in the pathopoiesis of MYOC gene. The mutational optineurin protein maight enhance the pathogenicity of MYOC gene through influence on the mRNA stability of MYOC gene. (3) The sequence alteration R545Q in OPTN gene is a common polymorphism in Chinese population, which is not related to POAG. (4) The sequence alteration IVS5+38T>G in OPTN gene is a common polymorphism which is not related to POAG in Chinese population, and it may be a characteristic sequence change in Chinese population.