Furthermore, our biomarker-response study in 12-month-old dogs showed that serum CCL2, MYOM3 and MSTN concentrations are useful biomarkers of the DE50-MD phenotype that are unaffected (CCL2 and MYOM3) or minimally affected (MSTN) by the low levels of physical activity performed by this age group. This evidence concerns the gene MSTN and Menkes disease.