Thus, such deletions/copy number reductions are not sufficient on their own to cause FSHD symptoms, when occurring on only one allele of FAT1. However, in all three positions, the proportion of FSHD cases (all cases included) who exhibited loss was significantly higher than the proportion of healthy controls carrying reduced copy numbers at the same spot (Figure 10C,D; X2 test, p values<0.016; <0.00075; and <0.00041, for exon 17; enhancer; and exon 16, respectively). Here, FAT1 is linked to Facioscapulohumeral dystrophy.