Figure 4. Electropherograms displaying intron 6 retention. A comparison of a portion of PRPF31 cDNA sequences between the unaffected (top: I-2) and the affected (bottom: II- 1) revealed intron 6 retention in all affected and asymptomatic individuals of family A. The green hatched box represents exonic region, and the red rectangular box indicates the start position of intron 6 retention (non-hatched) in the proband.