Figure 2. Confirmation of the mutation by PCR-RFLP method. The positions of the Fnu4HI restriction sites (GC/NGC) in the target sequence are represented (A). The schematic overviews show that one Fnu4HI restriction site was disrupted in the mutant form as a result of the mutation. In the wild-type form, there are two major fragments of 221 bp and 81 bp. In the disease form, one of the Fnu4HI restriction sites is disrupted, resulting in a longer fragment of 110 bp (boxed region). This longer fragment can only be observed in the affected family members (B). M, DNA Marker; Lane 1, unrelated normal control; Lane 2, senile cataract patient; Lane 3, unaffected member of the family; Lane 4 and 5, proband and his son; Lane 6, undigested PCR product.