Association of(G-T)n Dinucleotide Repeat Polymorphism of 5'-Flanking Region of TIGR/MYOC with Normal-Tension Glaucoma and Steroid-Induced Glaucoma

ABSTRACT

PURPOSE: We investigated whether TIGR/MYOC, a candidate gene for the primary open angle glaucoma(POAG) is also involved in the pathogenesis of normal tension glaucoma(NTG) and steroid-induced glau-coma(SIG). METHODS: Genomic DNA was extracted from the peripheral blood samples collected from 72 normal volunteers and 60 POAG, 47 NTG, 61 SIG patients. The genotype distribution of dinucleotide repeat polymorphism, (G-T)n microsatellite located 249 bp upstream of transcription start site was determined by direct sequencing of the Polymerase Chain Reaction(PCR) product. RESULTS: We found 6 alleles in the (G-T)n microsatellite of TIGR/MYOC ranging from 12 to 17, which differ slightly from that of previous reports. There was no obvious difference in the genotype distribution and allele frequency between the POAG group and the control group. However, a significant association of the microsatellite marker with SIG and, to a lesser extent, with NTG was observed. A significant increase in the frequency of (G-T)13/(G-T)13 genotype and a concomitant decrease in the frequency of (G-T)13/(G-T)14 genotype was seen in both the NTG and SIG group compared to that of the control group. In the SIG group, a significant decrease in the frequency of (G-T)14 allele was also observed compared to the control group, although the decrease did not contribute to the increase in the frequency of the allele. CONCLUSIONS: These findings suggest that a polymorphism in the 5 flanking region of the TIGR/MYOC is associated with patients with NTG and SIG.