One possibility that bears investigation is whether there are sequence variants allowing DUX4C expression in linkage disequilibrium with 4qA alleles, as DUX4C is very near to the 161 SSLP associated with FSHD, which being proximal to D4Z4 is in fact actually much more closely linked to DUX4C than to the poly A signal sequence. This evidence concerns the gene DUX4L9 and facioscapulohumeral muscular dystrophy.