IGF1 and Duchenne muscular dystrophy: Interestingly, label-free analysis of young and older DMD patients (G1 versus G2) revealed eight secreted proteins that increased in abundance with patient age (dopamine β-hydroxylase: 3-fold, adiponectin: 3-fold, serum amyloid P-component: 3-fold, insulin-like growth factor-binding protein complex acid labile subunit: 3-fold, β-Ala-His dipeptidase: 5-fold, insulin-like growth factor I: 5-fold).