Figure 5. DNA sequencing. Sequence chromatographs of the family. The healthy parents harbor normal DNA sequences (top), whereas the patient with congenital fibrosis of the extraocular muscles (CFEOM) exhibits a de novo 1056 C 1 → G mutation at the third nucleotide position of codon 352 (D352E) on exon 8 of the KIF21A gene locus.