Detection of a nonsense mutation (R240X) in the two-generation family ANF6. A- Pedigree showing the affected (dark filled) and unaffected (unfilled) family members. Cloned gPCR product digested with AvaI restriction enzyme confirms heterozygosity for the mutation in affected individuals (band sizes 206 bp, 131 bp, 75 bp in lane 2, 3) whereas the unaffected members carry only normal alleles with digested bands at 131 bp and 75 bp (lane 1 and 4). The unrelated normal control is shown on the left (UN). Undigested PCR product is on the right (UD). B- Normal chromatogram of PAX6 shows the presence of CGG (arginine) in exon 9. C- Direct sequencing of the genomic PCRs of the affected mother and (D) affected proband showing the presence of mutation, X-represents stop codon.