Because the mouse genome is devoid of the D4Z4 array containing DUX4 [132], but encodes only homologs of the human DUX4 gene that, when overexpressed, do not induce a strong muscle necrosis [133], mouse models for FSHD were designed to express the human DUX4 gene in a muscle-restricted manner from part of the human FSHD locus. This evidence concerns the gene DUX4 and facioscapulohumeral muscular dystrophy.