Telomere shortening is associated with D4Z4 hypomethylation in FSHD cells. The absolute level of DNA methylation at a single nucleotide level was determined by sodium bisulfite sequencing for three different regions within the D4Z4 sequence: BIS-5′ (21 CpGs represented by dots), BIS-mid (31 CpGs), and BIS-3′ (14 CpGs). For each sequence, several clones were analyzed from DNA obtained from control myoblasts with long or short telomeres and FSHD myoblasts with long or short telomeres. The distribution of methylated (black dots) or unmethylated (white dots) is represented for the different clones analyzed in the different conditions. The average percentage of methylation is indicated for each sequence.
