Figure 2.

Top, Haplotypes of 71 families with DM2. The three major affected haplotypes (A, B, and C) found in 71 families with DM2 analyzed are shown. The consensus haplotype A is indicated in gold. Minor deviations in repeat size are indicated by alternative colors, with a color key located below the figure. The markers span 2.2 Mb, and the distance of each marker from the DM2 CCTG expansion is denoted at the top of figure. The STR marker name and the repeat motif associated with each are designated. Bottom, Proposed ancestral origin of DM2 haplotypes. Proposed ancestral relationship between the major haplotype variants is shown, with haplotype B and C related to haplotype A, by a small number of ancestral recombination and microsatellite instability events.