Figure 3. PCR product sequencing chromatograms. A: The patient’s heterozygous (GCG)₁₁ expansion mutation is shown; the red arrow points to the start of the frameshift, and before it are the normal (GCG)₆ sequences. The heterozygous alleles are bimodal and marked “N”. B: The wild-type PABPN1 gene sequence from a healthy Chinese people is shown.