DUX4 and facioscapulohumeral muscular dystrophy: A recent chromosomal analysis of affected and unaffected 4q35 alleles has determined that FSHD is linked to a single nucleotide polymorphism located distal to the last D4Z4 repeat [19], which stabilizes the DUX4 transcript through polyadenylation and may result in elevated protein levels and cytotoxicity via still unknown mechanisms.