A single nucleotide polymorphism (SNP) in the promoter of the SPP1 gene, encoding the pleiotropic cytokine osteopontin, was the first variant to be associated with DMD severity, and more specifically to earlier loss of ambulation (LoA) and lower grip strength values (Pegoraro et al., 2011). This evidence concerns the gene SPP1 and Duchenne muscular dystrophy.