Figure 2. The USH2A gene harbors mutations in exons 20 and 70 of subjects with autosomal recessive retinitis pigmentosa. A: The USH2A gene structure is composed of 72 exons. B: Chromatograms of normal USH2A DNA sequence and subjects with autosomal recessive retinitis pigmentosa (arRP) show mutations at the c.4325 and c.15188 nucleotide positions in USH2A exons 20 and 70, respectively.