FIGURE 3.

Characterization of the mutant allele by repeat‐primed and long‐range PCR and PacBio sequencing. A, Representative plots of repeat‐primed PCR for TTTTA and TTTCA repeats from an unaffected (411 in Figure 1A) and affected individual (46 in Figure 1A). B, Gel image showing the amplification of mutant and WT alleles by long‐range PCR from 24 family members whose DNA was available. Identity of each sample (corresponding to Figure 1A) is marked on the top. Red circles mark two samples where mutant allele is detected by RP‐PCR but not robustly by long‐range PCR due to the low‐quality DNA. The ladder used is Mass Ruler DNA ladder mix where the top band is 10 kb. C, Size and pattern of the SAMD12 intronic pentanucleotide repeat motifs in each patient demonstrating its unstable nature