BSS analysis of genomic DNA samples distinguishes FSHD2 from FSHD1. (A) Partial pedigree for family 1090, which has a known FSHD2 mutation in the SMCHD1 gene that segregates with disease . (B) The 4qA BSS analysis (left) and DUX4 5’ BSS analysis (right) for genomic DNAs isolated from subjects in family 1090 or subject RB19518, as indicated. Genomic DNAs were isolated from fibroblasts for subject 1090-1 and PBMCs for all other subjects. Expected CpGs, based on predicted sequence composition of the unconverted region amplified, are listed in numerical order. Red boxes indicate methylated CpGs, blue boxes indicate unmethylated CpGs, and white boxes indicate no CpG detected at the expected site. The Q1 percent methylation is indicated for the 4qA BSS assays and the mean percent methylation is indicated for the DUX4 5’ BSS assays.