Nucleotide variants in OPTC. (A): Gene structure of Opticin. Bars and lines represent the exons and introns, respectively. Exon numbers and mutation/polymorphism therein are indicated. Within exons shaded and open boxes show coding sequences and untranslated regions, respectively. (B): SSCP images along with chromatograms showing nucleotide changes in OPTC of POAG patients identified in Table 1.