Detection of the C-to-T transition in genomic DNA obtained from various cell lines of patient LG2. DNA obtained from the indicated cell lines was amplified by PCR using a reverse primer located immediately after the mutation (position 1423-1445) and designed to create an HpaII restriction site CCGG on the wild-type sequence. Digestion of PCR products obtained from the wild-type sequence leads to the production of two fragments of 130 bp and 24 bp, whereas the mutated 154 bp product remains undigested. Digested PCR products were loaded on a 3% agarose gel and stained with ethidium bromide.